absolute value: (130, 131) The absolute value of a number, written with a double bar, is its distance from 0. Thus the absolute value of 3 is 3, the absolute value of –3 is 3.

acute angle: (362, 363) An angle less than 90 degrees in measure.

acute triangle: (366) A triangle in which every angle is acute.

addend: (18) A number that is added.

angle: (362)Two rays with the same endpoint.

arc: (372)A part of a circle.

area: (64, 65)The measure of a plane region in square units.

associative property: (6, 7) The sum (product) of three or more numbers is the same regardless of grouping: (a + b) + c = a + (b + c) and (ab)c = a(bc).

average: (46, 47) See mean.

axis: (148, 149) See coordinate axes.

base: (120) (in exponential notation) See exponents.

base: (6) (in numeration systems) The type of grouping used in a system. The decimal system is base ten.

base: (78-83) (of a polygon) Any side may be called the base of a polygon.

Base: (78-83) (of a solid) The area of whatever the base of the figure happens to be. (rectangle: A=lw   circle: A=pi r² etc.)

basic counting principle: (310, 311) If one thing can be done m  ways, and a second thing done n ways, then the two things can be done in m x n ways.

bias: (358) Systematic error in gathering data.

bis: (378) See bisect.

bisect: (378, 379) To divide a geometric figure into two congruent parts.

box and whiskers graph: (48, 49) A graph which shows how a collection of data are grouped and spread.

capacity: (85)The volume of a solid in terms of liquid measure.

central angle: (372) (of a circle) An angle with its vertex at the center of a circle.

chord: (372) (of a circle) A line segment with endpoints on the circle.

circle: (68, 69, 372, 373) A set of points which are all the same distance from a given point, called the center of the circle.

circumference: (68) (of a circle) The distance around the circle.

combination: (318, 319) A selection of a number of objects from a set, without regard to order.

commission: (284, 285) Pay based on a percent of sales.

commutative property: (6) The sum (product) of two numbers is the same regardless or order: a + b = b + a and ab = ba.

complementary angles: (362, 363) Pair of angles whose measures have a sum of 90 degrees.

composite number: (168, 169) A whole number with at least two different factors.

concentric circles: (372) Circles with the same center.

cone: (82, 83) A solid with a circular base and one vertex.

congruent: (440, 441) Having the same size and shape.

construction: (436, 437) A drawing of a geometric figure made only with compass and straightedge, and without measuring tools.

coordinate axes: (148, 149) Two intersecting lines (number lines) used for graphing ordered number pairs.

coordinates: (148, 149) An ordered pair of numbers that is matched with a pint in the coordinate plane.

cross products: (192) In the equation a/b = c/d, the products ad and bc are called cross products. The two ratios are equal if and only if ad = bc.

cube: (120, 121) (number) A number raised to the third power.

cube: (80, 81) (solid) A solid whose faces are congruent squares.

cylinder: (80, 81) A solid with parallel circular bases.

data: (12) A collection of facts, usually measures or frequency counts.

decagon: (66, 67) A polygon with ten sides.

degree: (362, 363) A unit of measure for angles, 1/90 of a right angle.

denominator: (192) In the fraction a/b, b is the denominator.

diagonal: (64-67) A segment connecting two nonadjacent vertices.

diameter: (372, 373)  (of a circle) A chord that contains the center of the circle.

differences: (134, 135) The number resulting from subtraction.

digit: (6) One of the basic symbols used in a place-value system. The base ten numerals are 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

distributative property: (6) Relates multiplication and addition as follows:a( b + c ) = ab + ac.

dividend: (136, 137) The number to be divided in a division problem.

divisible: (166, 167) One number is divisible by another if the remainder is zero.

divisor: (136, 137) See dividend.

dodecahedron: (366, 367) A solid with twelve faces.

edge: (66, 67) A segment that is the side of a face on a polygon.

ellipse: (478) A plane curve generated by a point P moving in such a way that the sum of the distances from P to two fixed points F and G never changes.

equally likely outcomes: (334-351) Outcomes that have the same chance of occurring.

equation: (94,95) A mathematical sentence using the equality symbol (=). x + 3 = 1 is an equation.

equilateral triangle: (366, 367) A triangle with all three sides the same length.

equivalent fractions: (192) Fractions that represent the same number.

estimate: (15) An approximation for a given number. Often used in the sense of a rough calculation.

event: (336, 337) A set of one or more outcomes in a sample space.

expanded form: () A number represented as a sum of products, such as
435 = 400 + 30 + 5 or 483.5 = 4 x 102 + 8 x 10 + 3 x 1 + 5 x 10-1.

exponent:(120,121) A number that tells how many times another number (the base) is to be used as a factor. In 125 = 5 x 5 x 5 = 5³ , 5 is the base and 3 is the exponent. (Also called the degree or power.)

experimental probability:(338,339) An estimate of the probability of an event found by repeated trials, such as tossing a coin repeatedly to determine the probability of getting a head.
Exp P(an event) = number of successful trials divided by number of trials in all.

expression:(54,55) (algebraic) Any combination of variables, numbers, operations, and parentheses that represents a number or range of numbers.

face:(76-79) Any polygonal region that is part of the surface of a polygon.

factor: (164,165) A number or expression to be multiplied.

factorial:(312,313) The products 1 x 2 x 3 x ….x (n –1) x n is n factorial. It is written n!. 0! is defined to be 1.

flowchart:(52,53) A diagram that organizes steps or instructions in a logical sequence.

fraction:(192,193,196,200,201) The quotient of two numbers in the form a/b.

frequency table: (42,43) A table that gives the number of times each outcome or group of outcomes occurs in a set of data.

function:(116,117) A rule, often given as an equation, table, or graph that relates each member (usually a number) from one set of numbers to a specific member of another set. The equation y = 2x is a function that doubles each number x.

greatest common factor (GCF): (176,177) The GCF of two or more numbers is the greatest number that is a factor of each of them.

greatest possible error (GPE): Half of the basic unit in which a measurement is given. Example: the GPE of a measurement of 13 ft is 0.5 ft.

heptagon:(366,367) A seven-sided polygon.

hexagon:(366,367) A six-sided figure.

hypotenuse: (402,403)The side of a right triangle opposite the right angle.

improper fraction: (192) A fraction whose numerator is greater than its denominator.

inductive reasoning:(452-455) Making a conclusion based on patterns, generalizing from examples.

integer: (130-149) A whole number or the opposite of a whole number.

inverse operations:(100,101) Operations that undo each other. Adding 5 is the inverse of subtracting 5.

interest: (296,297,306) A percent of money borrowed or loaned, as payment for the use of that money by the borrower.

irrational number:(396,397) A number that cannot be represented exactly as a quotient of two integers, such as the square root of 5 or – pi. Irrational numbers have nonrepeating, nonterminating decimal representations.

isosceles triangle:(366,367) A triangle with at least two congruent sides.

least common denominator (LCD): (200,201) The LCM of the deminominators of two or more fractions. The LCD of 5/6 and 3 /4 is 12.

least common multiple (LCM): (178,179) The smallest nonzero number that is a multiple of two or more whole numbers is their LCM. The LCM of 6 and 4 is 12.

linear function: (152,153) A function whose graph forms a straight line. The equation for a linear function can always be written as y = ax + b, where a and b are any numbers.

lowest-terms fraction: (192,193) A fraction for which the GCF of the numerator and denominator is 1.

mean: (46,47) The quotient obtained when the sum of two or more numbers is divided by the number of addends. An average is another name for the mean.

median: (46,47) The middle number of a set of numerical data arranged from least to greatest. If there is no single middle number, it is the mean of the two middle numbers.

midpoint: (376-379) That point halfway between the endpoints of a line segment.

mixed number: (192,196,202,203) A number that has both a whole number part and a fractional part.

mode: (46,47) The most common value in a set of data. There may be no mode, one mode, or several modes.

multiple: (164,165) (of a number) Any product of that number and a whole number.

negative integer: (134,135) Number that is less than 0 and the opposite of a whole number.

nonagon: (366,367) A nine-sided polygon.

numeral: (10,11) A symbol for a number.

numerator: (192) For a fraction x/y the numerator is x.

obtuse angle: (362,363) An angle whose measure is greater than 90 degrees and less than 180 degrees.

obtuse triangle: (366,367) A triangle with one obtuse angle.

octagon: (366,367) An eight-sided polygon.

ones property: (6) See property of one.

opposites property: (194) The sum of any number and its opposite is zero.

ordered pair: (150,151) Two numbers in a particular order, often associated with points on the coordinate plane.

origin: (150,151) The ordered pair ( 0, 0 ) at which coordinate axes intersect.

outcome: (334-339) See sample space and event.

parallel lines: (362,363,376,377) Lines in the same plane, that do not intersect.

parallelogram: (66,67) A quadrilateral with opposite sides parallel (and equal in length).

pentagon: (366,367) A five-sided polygon.

percent: (256,257) Literally, “per hundred.” 6% means the ratio 6 per hundred.

perimeter: (71) The sum of the length of the sides of a polygon.

period: (4,5) In a decimal numeral, each group of three digits, starting with the unit digit, is a period.

permutation: (312,313,318) A selection of a number of objects from a set, and in a particular order.

perpendicular: (376,377) Two flat figures (lines, planes, polygons, segments) are perpendicular if they meet at right angles.

perpendicular bisector: (378,379) A line that is perpendicular to a segment and bisects it.

pi: (68) The ratio of the circumference of a circle to its diameter; and irrational number approximated by 3.141592654.

place value: (4,5) The value given to a place a digit may occupy in a numeral. In the decimal system, the value of each place is 10 times the value of the place to its right.

polygon: (366,367) A plane figure formed by line segments that is closed (which  means  it has one inside and one outside.)

polyhedron: (388) A solid whose surface is made up of polygonal regions. It is closed.

positive number: (130,131) A number greater than zero.

precision: (50,51) One measurement is more precise than another if the first measurement uses a smaller unit and has a smaller GPE.

prime factorization: (172,173) The expression of a composite number as a product of prime factors.

prime number: (168,169) A whole number greater than 1 that has only the factors of 1 and itself. There are exactly two factors. (1 is not a prime number because it only has 1 factor.)

principal: (296,297) Money loaned, usually at a given interest rate and for a specified time.

prism: (80,81) A solid whose bases are congruent parallel polygons, and whose sides are parallelograms.

probability: (334,335) (of an event) The ratio of the number of ways an event can occur to the total number of possible outcomes.

product: (136,137) The result of multiplication.

properties of equality: (6,7) Properties that allow one to change each side of an equation in the same way ( such as adding the same value to each side), so that the result is also an equation.

property of one: (6,7) The product of any number x and 1 is x.

property of zero: (6,7) The sum of any number x and 0 is x.

proportion: (226,227) An equation stating that two ratios are equal.

protractor: (362,363) An instrument for measuring the number of degrees in an angle.

pyramid: (82,83) A solid with a polygonal base and triangular faces with a common vertex.

Pythagorean Property (Theorem): (402,403) In a right triangle, the sum of the areas on the squares of the legs equals the area on the square of the hypotenuse. The formula is a² +  b²  = c².

quadrilateral: (366,367) A four-sided polygon.

quotient: (136,137) The result of division. See also dividend.

radius: (372) A segment whose endpoints are the center of a circle and any point on the circle. Also the length of such a segment. Half the diameter.

random: (350,351) An object (number) is selected randomly if it is selected in a way that gives all possible objects an equal chance.

rate: (228,229) A ratio of two quantities with different units of measure..

ratio: (226,227) A comparison of two numbers, usually.

rational number: (196-199) The quotient of two integers.

ray: (378,379) A part of a line with one endpoint; a ray continues without end in one direction.

real number: (164-181) A rational or irrational number; any number on a number line.

reciprocals: (208,209) Two numbers whose product is 1. The reciprocal of x is 1/x.

rectangle: (66,67) A parallelogram with four right angles.

reflection: (422,423) A transformation (motion) of a geometric figure as be a mirror. Triangle ABC and Triangle A¹ B¹ C¹  are reflections of each other.

regular polygon: (366,367) A polygon with congruent sides and congruent angles.

regular polyhedron: (366,367) A solid, such as a cube, all of whose faces are congruent regular polygons. There are only five different regular polyhedra (also called Platonic solids).

relatively prime:  (168,169) Two numbers are relatively prime if their GCF is 1.

repeating decimal: (198) A decimal whose digits after a given place repeat endlessly. 25 divide 99 = 0.25252525. . . = 0.25

rhombus: (66,67) A parallelogram with congruent sides.

right angle: (406-409) An angle that measures 90 degrees.

right triangle: (406-409) A triangle with one right angle.

rotation: (424,425) A transformation (motion) of a geometric figure resulting form a tuwn about any given point. Triangle ABC and  Triangle A¹ B¹ C¹ are rotations of each other.

sample space: (334,335) The set of all possible outcomes of an experiment. The sample space of a coin toss consists of the two outcomes heads and tails.

scale drawing: (234,235) A drawing of an object in which the lengths in the drawing are proportional to the actual lengths of the object.

scalene triangle: (366,367) A triangle all of whose angles have different measures.

scientific notation: (214,215) A system of writing numbers using exponents and powers of ten. Thus, 2,300,000 would be written 2.3 x 106.

secant: (372) A line that intersects a circle at two points.

segment: (378,379,436,437) Two points and all the points in between them.

similar figures: (438,439) Figures that are the same shape, but not necessarily the same size.

skew lines: (426) Lines in space that are not parallel and do not intersect.

solid: (76-83) A continuous three-dimensional geometric figure whose points do not all lie in the same plane.

space figure: (76-83) See solid.

sphere: (80-83) A solid composed of all points that are the same distance from a given point (the center).

square: (66,67) (geometry) A quadrilateral with four congruent sides and four congruent angles.

square: (392,393) (numeration) The square of a number p is q = p x p, also written p².

square root: (392,393) The square root of x of a number x is a number y such that y x y = x. If y is positive, then –y is the negative square root.

stem and leaf plot: (40,41) A system for organizing and presenting numerical data so that frequencies can be compared.

straight angle: (362,363) An angle with a measure of 180 degrees; a straight line.

supplementary angles: (362,363) Two angles with measures that add to 180 degrees.

surface area: (76,77) The sum of the areas of all the surfaces of a solid.

tangent: (372) (to a circle) A line that intersects the circle in one point.

tangent ratio: (242,243) In a right triangle, the tangent ratio of a lesser angle is the quotient of the length of the let opposite the angle and the length of the leg that makes up part of the angle.

terminating decimal: (198) A decimal that represents the quotient of an integer and a power of ten.

tetrahedron: (366,367) A polyhedron with four faces, all triangles.

tesselation: (368,369) An infinite set of congruent figures that can be fitted together without overlap to fill a plane completely, like floor tiles.

translation: (420,421) A transformation (motion) of a geometric figure by a side, and without rotation.

transversal: (362,363) Given two lines, any line that intersects them is a transversal of the two lines.

trapezoid: (66,67) A quadrilateral with exactly one pair of parallel sides.

tree diagram: (310,340,341) A way to diagram sequences of possible options or divisions.

triangle: (366,367) A three-sided polygon.

unit: (230,231) An amount or quantity used as a standard of measure.

unit price: (230,231) The cost per unit (such as pound, liter, ounce) of a given item, used to simplify comparing prices of similar goods.

variable: (22,23) A letter or other symbol that stands for a number ( or numbers) in an expression or mathematical sentence.

vertex: (364,365) The common point of the two rays of an angle. Also the common point of two sides of a polygon, or the common point of three or more faces of a polyhedron.

volume: (78-83) The measure of a solid, in terms of a unit cube.

whole number: (196-207) Any of the numbers 0, 1, 2, 3, 4, . . .

zero property: (6) See property of zero.
 

Source: Addison-Wesley Mathematics 8th Grade edition

Addison-Wesley Publisher
Copyright: 1991
ISBN: 0-201-27801-4