50 Essential Math Vocabulary Words in English

Key takeaways

• Math vocabulary in English is essential for students in English-medium schools, international exams (TOEFL, IELTS, GRE, GMAT, SAT), and science and engineering fields.
• Many math terms come from Latin and Greek roots, which makes them look unfamiliar but also predictable once the roots are learned (bi- means two, tri- means three, poly- means many).
• Operations vocabulary follows specific grammatical patterns in English that differ from how equations are read in other languages.
• Geometry, algebra, statistics, and measurement each have distinct vocabulary sets that are best studied by domain rather than as a single undifferentiated list.

A student who understands mathematics in their first language but struggles to follow an English-medium lecture, exam question, or textbook is not facing a math problem: they are facing a vocabulary problem. Knowing the answer is not enough if you cannot read the question.

italki connects learners with English teachers who specialize in academic English and can build the subject-specific vocabulary you need for your field.

This guide covers how to say math operations in English, arithmetic vocabulary, geometry vocabulary, algebra vocabulary, statistics and probability vocabulary, measurement vocabulary, word problem vocabulary, and the Latin and Greek number prefixes that make technical math terms easier to decode.

How to say math operations in English

One of the first places learners get confused is how English speakers read equations aloud. The same equation can be expressed in several grammatically correct ways. Here are the most common patterns for each operation.

Operation	Equation	English phrasings
Addition	5 + 3 = 8	Five plus three equals eight / Five and three is eight / The sum of five and three is eight
Subtraction	10 – 4 = 6	Ten minus four equals six / Four subtracted from ten is six / The difference between ten and four is six
Multiplication	6 x 7 = 42	Six times seven is forty-two / Six multiplied by seven equals forty-two / The product of six and seven is forty-two
Division	20 / 4 = 5	Twenty divided by four is five / The quotient of twenty and four is five / Four goes into twenty five times
Exponents	5^2 = 25	Five squared is twenty-five / Five to the power of two is twenty-five
Square roots	V25 = 5	The square root of twenty-five is five

Note on equals: In informal speech and classroom settings, English speakers often say is instead of equals when reading equations: five plus three is eight. Both are correct. Is sounds more natural in spoken math, while equals appears more often in written instructions and formal contexts.

Note on large numbers: English uses a comma (,) as the thousands separator and a period (.) as the decimal point. So one thousand two hundred and fifty is written 1,250, and one point five is written 1.5. Many other languages use these symbols in reverse order, which causes confusion on international exams.

Basic arithmetic vocabulary

These terms appear across all levels of math and in word problems at every stage of learning.

Term	Definition	Example
Sum	The result of addition	The sum of 7 and 3 is 10
Difference	The result of subtraction	The difference between 10 and 4 is 6
Product	The result of multiplication	The product of 4 and 5 is 20
Quotient	The result of division	The quotient of 20 and 4 is 5
Remainder	What is left after division when the result is not a whole number	17 divided by 5 is 3 remainder 2
Factor	A number that divides evenly into another	3 is a factor of 12
Multiple	The result of multiplying a number by a whole number	15 is a multiple of 5
Prime number	A number divisible only by 1 and itself	7, 11, 13 are prime numbers
Composite number	A number with more than two factors	12 is composite (factors: 1, 2, 3, 4, 6, 12)
Numerator	The top number in a fraction	In 3/4, the numerator is 3
Denominator	The bottom number in a fraction	In 3/4, the denominator is 4
Fraction	A number expressed as one integer over another	3/4 (three quarters)
Decimal	A number expressed with a point, not a fraction	0.75
Percentage	A number out of 100	75% (seventy-five percent)
Ratio	A comparison of two quantities	The ratio of boys to girls is 3:2
Proportion	Two ratios that are equal	1:2 = 3:6 is a proportion
Square root	A number multiplied by itself to get the original	The square root of 16 is 4
Exponent	A number showing how many times a base is multiplied by itself	In 2^3, the exponent is 3
Power	The result of a base raised to an exponent	2^3 = 8 (two to the third power is eight)

Geometry vocabulary

Geometry has its own vocabulary that appears in school curricula, standardized tests, and technical fields including engineering, architecture, and design.

Term	Definition
Point	An exact location in space with no dimensions
Line	A straight path extending in two directions with no endpoints
Line segment	A part of a line with two endpoints
Ray	A part of a line with one endpoint, extending infinitely in one direction
Angle	The space between two rays that share an endpoint
Acute angle	An angle less than 90 degrees
Right angle	An angle of exactly 90 degrees
Obtuse angle	An angle greater than 90 degrees and less than 180 degrees
Triangle	A polygon with three sides and three angles
Equilateral triangle	A triangle with all three sides equal
Isosceles triangle	A triangle with two equal sides
Scalene triangle	A triangle with no equal sides
Quadrilateral	A polygon with four sides
Rectangle	A quadrilateral with four right angles
Square	A rectangle with all four sides equal
Circle	A set of points all the same distance from a center point
Radius	The distance from the center of a circle to its edge
Diameter	The distance across a circle through its center (twice the radius)
Circumference	The distance around the outside of a circle
Area	The size of a surface, measured in square units
Perimeter	The total distance around the outside of a shape
Volume	The amount of space inside a three-dimensional shape
Parallel	Lines that run in the same direction and never meet
Perpendicular	Lines that meet at a right angle (90 degrees)
Congruent	Shapes that are the same size and shape
Similar	Shapes that have the same shape but different sizes

An English language tutor can help you read geometry word problems aloud and identify the terms you are skipping over, which is one of the most common reasons students miss points on standardized tests even when they know the underlying mathematics.

Algebra vocabulary

Algebra introduces a different category of vocabulary because it describes relationships between numbers and unknown quantities rather than specific shapes or operations.

Term	Definition	Example
Variable	A letter that represents an unknown number	In 3x + 5, x is the variable
Constant	A fixed value that does not change	In 3x + 5, the number 5 is the constant
Expression	A combination of numbers, variables, and operations	3x + 5 is an expression
Equation	A statement that two expressions are equal	3x + 5 = 11 is an equation
Inequality	A statement that one expression is greater or less than another	3x + 5 > 11 is an inequality
Coefficient	The number multiplied by a variable	In 3x, the coefficient is 3
Term	A single number, variable, or product of numbers and variables	In 3x + 5, there are two terms
Linear equation	An equation whose graph forms a straight line	y = 2x + 3 is a linear equation
Quadratic equation	An equation with a variable raised to the second power	x^2 + 3x + 2 = 0 is quadratic
Solution / Root	The value of a variable that makes an equation true	x = 2 is the solution to x + 3 = 5
Slope	The steepness of a line, measured as rise over run	A slope of 2 means the line rises 2 units for every 1 unit across
Intercept	The point where a line crosses an axis	The y-intercept of y = 2x + 3 is 3
Function	A relationship where each input has exactly one output	f(x) = 2x + 3 is a function

Statistics and probability vocabulary

Statistics vocabulary appears in research, business, data analysis, science reports, and university coursework across many disciplines.

Term	Definition
Mean	The average: add all values, divide by the count
Median	The middle value when data is arranged in order
Mode	The value that appears most often in a data set
Range	The difference between the highest and lowest values
Standard deviation	A measure of how spread out values are from the mean
Probability	The likelihood of an event, expressed as a number between 0 and 1
Data	Information collected for analysis
Sample	A smaller group selected to represent a larger population
Population	The entire group being studied
Frequency	How often a value appears in a data set
Outlier	A value that is significantly higher or lower than most others
Bar chart	A graph that uses rectangular bars to show quantities
Pie chart	A circular chart divided into sections showing proportions
Scatter plot	A graph showing two variables as dots on an x-y axis
Hypothesis	A proposed explanation that can be tested with data

Measurement vocabulary

Measurement vocabulary is essential for science, engineering, cooking, travel, and any context where quantities matter. English-medium settings use a mix of metric and imperial units depending on the country and field.

Length:

Imperial	Metric
Inch (in)	Centimeter (cm)
Foot (ft)	Meter (m)
Yard (yd)	Kilometer (km)
Mile (mi)

Weight:

Imperial	Metric
Ounce (oz)	Gram (g)
Pound (lb)	Kilogram (kg)

Volume:

Imperial	Metric
Fluid ounce (fl oz)	Milliliter (ml)
Gallon (gal)	Liter (L)

Temperature: Fahrenheit (F) is used in the United States. Celsius (C) is used in most other countries and in all scientific contexts. The conversion formula: C = (F – 32) x 5/9.

Time units: second, minute, hour, day, week, month, quarter (three months), year, decade (ten years), century (one hundred years).

Word problem vocabulary

Word problems test both math knowledge and reading comprehension in English. These are the terms that tell you what the problem is actually asking you to do.

Term	What it means in a word problem
Find	Calculate and state the value
Solve	Work through the steps to reach the answer
Calculate	Perform the arithmetic
Determine	Figure out which value or option applies
Estimate	Give an approximate rather than exact answer
Approximate	Round to a nearby value
Prove	Show through steps that a statement is true
Show that	Demonstrate a given result through working
Evaluate	Calculate the value of an expression
Simplify	Reduce to the simplest form
Expand	Multiply out brackets
Factor	Rewrite as a product of factors
Given that	A condition that is stated as true for the problem
In terms of	Express the answer using a specific variable or unit
Therefore	Signals the conclusion following from previous steps
Hence	Used to introduce a result that follows logically
It follows that	Shows the next logical step
What is the value of	Asks for a specific numerical answer

TOEFL vocabulary overlaps with math and science test preparation because both require precise academic English.

Number prefixes from Latin and Greek

Many math and science terms in English contain a Latin or Greek root that indicates a number. Learning these roots allows you to decode unfamiliar terms without memorizing each one individually.

Prefix	Meaning	Examples
Uni- / Mono-	1	Unicycle, monopoly, monolingual
Bi- / Di-	2	Bicycle, bilateral, dioxide, diameter
Tri-	3	Triangle, trigonometry, trillion
Quad- / Tetra-	4	Quadrilateral, quadrant, tetrahedron
Penta-	5	Pentagon, pentagram
Hexa-	6	Hexagon, hexadecimal
Hepta-	7	Heptagon
Octa-	8	Octagon, octave
Nona-	9	Nonagon
Deca-	10	Decade, decimal, decagon
Centi-	100 (or 1/100)	Century, centimeter, percent
Milli-	1,000 (or 1/1,000)	Millennium, millimeter, milliliter
Kilo-	1,000	Kilometer, kilogram, kilowatt
Mega-	1,000,000	Megabyte, megawatt

Knowing that bi means two tells you immediately that a bilateral equation involves two sides. Knowing that poly means many (from Greek polys) tells you that a polygon is a many-sided shape and a polynomial is an expression with many terms.

English vocabulary practice becomes easier when you notice word families and roots that repeat across academic subjects.

The vocabulary gap in math is often invisible until an exam or a classroom discussion reveals it. Understanding the mathematics is one thing; understanding the English used to describe the mathematics is a separate skill that rewards direct study. italki has 30,000+ expert tutors trusted by over 10 million learners worldwide, and many specialize in academic English and subject-specific vocabulary. Book a trial lesson and work with a teacher who can help you read, write, and speak math vocabulary in English with confidence.

FAQ

Why is it important to learn math vocabulary in English specifically?

International exams like the SAT, GRE, and GMAT, as well as English-medium university courses in STEM fields, require students to read and answer questions in English mathematical language. Students who understand the underlying mathematics but cannot parse the English phrasing of a word problem lose points unnecessarily. Learning math vocabulary in English is a targeted investment with measurable exam outcomes.

What is the difference between mean and average in English math vocabulary?

In everyday English, average is used informally to mean the mean (add all values and divide by the count). In statistics, average can technically refer to the mean, median, or mode, but mean specifically refers to the sum-divided-by-count calculation. On standardized tests and in technical writing, mean is preferred for precision.

How do I read fractions aloud in English?

Read the numerator as a regular number and the denominator as an ordinal number. One third (1/3), two fifths (2/5), three quarters (3/4). One half (1/2) and one quarter (1/4) are irregular and use those specific words rather than one second or one fourth (though one fourth is acceptable in American English for 1/4). For fractions with large denominators, say the numerator then over then the denominator: seven over eleven for 7/11.