This tag is for questions about the usage and meaning of mathematical terminology and the names for mathematical entities in English.

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110
votes
12answers
10k views

What do you call a disk with a hole in the middle?

Compact Discs, washers and Aerobie frisbees are all disks with a hole in the middle. Is there a word (either mathematical or not) to describe this shape? I mean the specific case of a round hole in a ...
81
votes
3answers
11k views

Why does “quadratic” describe second power while “quad” usually describes “four”?

In mathematics, quadratic means "involving the second and no higher power of an unknown quantity or variable". But the prefix quad- usually describes something that has to do with four, such as ...
79
votes
26answers
7k views

How to read “E = (mc)²” so as not to mistake for “E = mc²”

According to one of the questions already asked on EL&U, “E = mc²” is read as E equals M C squared. How do we read “E = (mc)²” so that it is not mistaken for “E = mc²”?
54
votes
8answers
6k views

Is -1 singular or plural?

Do we say "-1 thing" or "-1 things"? Edit: I am interested in both of these cases: "two things minus one thing(s)" and the quantity "minus/negative one thing(s)." Bounty: While there are some good ...
32
votes
6answers
24k views

Use of “I”, “we” and the passive voice in a scientific thesis [duplicate]

Possible Duplicate: Style Question: Use of “we” vs. “I” vs. passive voice in a dissertation When the first person voice is used in scientific writing it is mostly ...
32
votes
8answers
11k views

X, Y, Z — horizontal, vertical and …?

When working in a 2D coordinate system you could say that X is the horizontal axis and Y is the vertical axis. Extending this to 3D, is there a similar word for the Z axis? (I'm aware of Width, ...
29
votes
2answers
1k views

Rhetoric vs. Mathematics: ellipsis/ellipse, parable/parabola, hyperbole/hyperbola

Do ellipsis, parable, and hyperbole from rhetoric have anything in common with the geometric curves ellipse, parabola, and hyperbola used in mathematics? There are three geometric curves known as ...
22
votes
1answer
1k views

What's the name of this letter? [closed]

I came upon this letter when reading a book, I couldn't find its name on the internet, you can imagine how hard it is to search about it. What is the name of the letter that follows "sample space"? ...
21
votes
7answers
2k views

(k+1)th or (k+1)st?

Mathematicians commonly have to form ordinals from variables: you might look at the kth element of a sequence, for example. When the variable is a single letter, the ordinal is always formed with the ...
19
votes
4answers
2k views

How is a' in mathematics pronounced?

It often happens that two or more similar values are distinguished with the ' symbol, e.g. a, a', a'' and similar. How is this pronounced?
19
votes
5answers
2k views

Is “iff” considered a real word or just an abbreviation?

I wonder if "iff" is considered a real word (as LEO says) or is it just an abbreviation (as in Wiktionary)?
19
votes
4answers
2k views

Transform or transformation?

Is there a difference between the words transform (noun) and transformation? Let me describe my problem. I have a mathematical model which I can transform into a better model with help of a data ...
17
votes
4answers
1k views

What is the term for an integer one larger than a given integer?

I'm looking for a concise term to say a number must be exactly one higher than a previous number. None of "subsequent", "incremental", or "next" seem to convey the restriction that it must be ...
16
votes
8answers
4k views

Why do we say “lowest common denominator” when we mean “greatest common divisor”?

For example, we could say HTML is the lowest common denominator on the web", because one can be sure all web browsers are able to render HTML (but not Flash or Java). If I want my web page to show ...
15
votes
2answers
3k views

Where does the word “totient” come from?

In math we learn about the "totient function". It rhymes with "quotient" when math teachers pronounce it. But I cannot find the definition or etymology of this word in any dictionary, nor on any ...
14
votes
4answers
2k views

Is there a shorter term for “divided by” in American English?

Given the following expression: 5 (+-×÷%) 4 You would say "5 plus 4," "5 minus 4," "5 times 4," "5 divided by 4," and "5 mod(ulo) 4" respectively. As far as I know, "divided by" does not have ...
14
votes
3answers
1k views

What is the proper term for a ternary digit?

A binary digit is a bit. Is there an equivalent term for a three-state digit? (e.g., a digit representing true, false, or unknown)
14
votes
1answer
5k views

Trapezium/trapezoid — why are the US/UK definitions swapped around?

These are the US definitions... Trapezoid — a 4-sided flat shape with straight sides that has a pair of opposite sides parallel. Trapezium — a 4-sided flat shape with straight sides and NO parallel ...
13
votes
4answers
8k views

How to read exponential expressions, e.g., “2^16”?

How do you say the mathematical function in English: x^y (or xy) For example, how do you say 2^16 (or 216) I know ^ means 'power' or 'exponentiate', but that is the name of the ...
13
votes
5answers
9k views

Does “either A or B ” preclude “both A and B”?

In mathematics, "A or B" includes "A and B". Does "either" mean "A or B but not (A and B)" or does it include the possibility of "A and B"? The context might be mathematics, formal logic or ordinary ...
13
votes
5answers
9k views

Difference between “computation” and “calculation”

If the words computation and calculation are not perfect synonyms what is the difference between them? Which one describes more accurately what is done by a person computing or calculating something ...
12
votes
5answers
1k views

What is an adjective for a very large negative number?

A number that is very large (but not infinite) such as 1,000,000,000,000,000 could be called huge, enormous, large, big, gigantic, etc. A number that is very small such as 0.000000001 could be called ...
10
votes
3answers
3k views

What reasoning is behind the names of the trigonometric functions “sine”, “secant” and “tangent”?

The meanings of these words are very similar: the sine of an angle in a right triangle is the ratio of the opposite side to the hypotenuse; the secant is the ratio of the hypotenuse to the adjacent ...
9
votes
4answers
992 views

Pronunciation of the big-O notation

How should I pronounce the following things? (These are complexities of algorithms.) O(n) O(n*log(n)) O(n^2)
9
votes
2answers
8k views

Should I use the singular or plural verb in mathematical formulae (“Two and two make/makes four”)?

I remember somebody correcting me once when I said, "Two and two makes four", since the conjunction and would imply the use of a plural verb. They would prefer I said: Two and two make four. ...
9
votes
1answer
727 views

Use of an Apostrophe in Maths Place Values

In mathematics, when you're discussing the concepts behind different number bases, it's often necessary to refer to a digit's place. For example, in the following "base 10" number (the number system ...
8
votes
4answers
3k views

How can I form a word like “quadruple” for any number I want?

I'm not sure what these are called, but how can I form a word like "quadruple" for any number I want? Like 5× as much is quintuple, what is 31× as much or 147× as much? I want to know how they are ...
8
votes
3answers
25k views

Are there any differences between “oval” and “ellipse”?

Are there any differences between "oval" and "ellipse"?
8
votes
2answers
1k views

What is the derivation of the statistical term “Histogram”?

There are conflicting definitions of origin. Unclear as to whether it is derived directly from the Greek, coined by Pearson, or used and named prior to Pearson. Refer to "The History of Histograms - ...
8
votes
1answer
170 views

How to punctuate math fractions?

I was doing the Writing and interpreting decimals exercise on Khan Academy and was asked the following question: What is nine and three hundred two thousandths in numerical form? I read it as ...
8
votes
1answer
612 views

The Condition Holds vs is Satisfied vs Obtains

In mathematical/scientific texts, conditions that are true (within context) are said to hold be satisfied obtain (the last one was news for me) My question is whether there is nuance in meaning ...
7
votes
7answers
1k views

How can I describe a “one or more” condition (one that has many options; a “non-boolean”)?

Generally speaking a boolean condition is understood to be an "either/or" relationship; for example, something is hot or cold. What's do you call a "one or more" condition, e.g. something that can ...
7
votes
4answers
2k views

How to pronounce “nₒ” properly

People here (Hong Kong) like to pronounce n0 ("n subscript zero") as "N-nor"; "N-zero" seems to be acceptable. I am wondering what's the most popular pronunciation in English. I am actually a little ...
7
votes
3answers
1k views

When do we use “suppose” and when “let”?

As a matter of fact, these two words are used a lot in mathematical contexts. Often, we use them interchangeably; but I do realize that that might not be correct. What should I do about this matter? ...
7
votes
5answers
1k views

Is there a word for a class of circular shapes?

I'm not sure if this belongs here, but I'm wondering if there is a word for a class of circular shapes? Thinking about this hierarchically: * Shape * Polygon * Square * Rectangle * ...
7
votes
4answers
6k views

“Lower number” vs. “smaller number”

Is −9 a smaller number than −8? And is −9 a lower number than −8? What is the difference between lower and smaller here?
7
votes
2answers
180 views

Symbol and sign in mathematics

Mathematical notations are usually called symbols in the large, yet particular symbols seem to be blessed, they are often called signs ('equals sign', 'multiplication sign', ...). Is there a ...
6
votes
2answers
465 views

Etymology of “magma” in abstract algebra

Magma is one of those beautiful words of Greek origin (μάγμα) that arouses the child and the wild in me, making me think of volcanoes. I just found out, though, that it is also used in mathematics to ...
6
votes
2answers
556 views

Etymology of “regression”

What is the etymology of "regression" as in finding the coefficients of polynomials?
6
votes
2answers
178 views

word for bringing a number to its absolute value

In mathematics, the absolute value of a number n is either −n if n is negative or n itself if otherwise. Is there a single word or shorter description for the replacement of n with its absolute ...
6
votes
1answer
189 views

“Commutivity” or “commutativity”

I see commutivity used in contexts where the meaning appears to be the same as commutativity. Here are an example from physics and another example. Is commutivity incorrect? Does it differ from ...
6
votes
3answers
178 views

“That… be” construction

We will make the convention that exact categories be skeletally small. Is this construction (used in a mathematical context) correct? There is something that strikes me as odd in that "be". ...
5
votes
5answers
510 views

“Let's/We let A be a variable”

Suppose I am giving a math talk and I am going to write on the board Let A be a variable. What do I say while I write? Can I say Let's let A be a variable or should I write We let A be a variable and ...
5
votes
4answers
962 views

How is the sentence “The symbol % is used to represent percent” read?

I have three sentences in my math textbook that use the symbol %. The symbol % is used to represent percent. Usually denoted by the symbol %. Most calculators have a key with the % symbol ...
5
votes
2answers
3k views

“integer multiple” vs. “integral multiple”

Nine is an integer multiple of three. Nine is an integral multiple of three. Which is more common? If both are accepted, what's the subtle difference between them?
5
votes
3answers
1k views

Why don't years have commas?

For example, if one asks "what's two thousand plus two thousand", one could write it like this: 2,000 + 2,000 But when one writes the date: January 2, 2000 So why do we put commas when ...
5
votes
2answers
56 views

Fluents and Fluxions

When calculus was first being developed, the terms "fluent" and "fluxion" appeared quite often in the Newtonian works. I am wanting to know the etymology behind these words. I assume that "fluents" ...
4
votes
7answers
3k views

Does “less than” really mean “subtracted from”, or is it bad English?

I got involved in a discussion about some Math problems provided in the local primary school education: 20 more than 543 is 563 25 less than 261 is 236 155 less than 310 is 155 355 more than 1233 is ...
4
votes
5answers
5k views

Divide two into four and Divide two by four

Why does "divide two into four" equal two, and "divide two by four" equal one half? Correct if I am wrong, but this what I have learned recently.
4
votes
5answers
17k views

Why is “a 100% increase” the same amount as “a two-fold increase”?

and is such interpretation the norm? When something went from 4 units to 8 units, most authoritative sources seem to agree with the use of "a two-fold increase", even though what was actually ...