# Questions tagged [terminology]

For questions about terms, definitions and related concepts used in science and mathematics.

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### When and by whom was the term 'momentum' introduced?

We know that up to 1726, when the third edition of the Principia was published, the name for $m\vec v$ was: quantitas motus. Do you know who substituted that with another Latin word: 'momentum'?
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### Why are microwaves called "microwaves", when they are much longer than a micrometer?

If "millimeter waves" have a wavelength of about 1 mm, one might linguistically expect microwaves to have a wavelength of about three orders of magnitude less, not the same or greater. How did ...
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### Why is the Sophie Germain Identity called thus?

Several authors (z.B.: Arthur Engel in his Problem-Solving Strategies, Alexander Bogomolny in this entry of the Cut the Knot website) refer to the following (straightforward) consequence of the ...
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### Why is the Heaviside step function named after Heaviside?

The Heaviside step function is usually defined as $$\theta(x)=\left\{\begin{array}{ll}0&\text{if }x<0\\\tfrac12&\text{if }x=0\\1&\text{if }x>0.\\\end{array}\right.$$ It is ...
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### How is the word kernel associated with distributions?

I am trying to rationalize the meaning of the term kernel, especially when it is associated with distributions. The English and German etymology all show that the literal meaning is corn (English) and ...
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### What is the reason for the 'electromagnetism terminology' when discussing the conserved quantities found through Noether's theorem?

In (theoretical) physics, it is customary to describe the system under consideration in terms of the Lagrangian. One of the major advantages of this approach is that it allows us to analyze the ...
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### What is the etymology of the mathematical terms "sheaf, stalk, germ"?

The peculiar agricultural terminology commonly used in algebraic geometry and category theory, "sheaf", "stalk", "germ", is quite well-known. A sheaf is pictured as something like a bundle of stalks, ...
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### Why is one of Maxwell's equations named after Ampère? Who first named it after Ampère?

Ampère never wrote down what is confusingly called "Ampère's circuital law," not even the form without the displacement current term, as Ampère never dealt with the field concept.* Maxwell derived \...
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### First use of term "Hilbert's Nullstellensatz"

This year (2021) marks the 100th anniversary of Emmy Noether's 1921 paper in which she introduced Noetherian rings and proved the primary ideal decomposition for them. The original version of her ...
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### Who was the first to use the "does not exist" sign ∄?

Who was the first to use the "does not exist" sign ∄? I'm aware that Giuseppe Peano originated serifed ∃ and, moreover that Whitehead and Russell repurposed Peano's serifed ∃; I'm also aware that ...
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### Whence “homomorphism”, “homomorphic”?

The kernel question leads to another : Today, homomorphism (resp. isomorphism) means what Jordan (1870) had called isomorphism (resp. holoedric isomorphism). How did the switch happen? “Homomorphic” ...
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### What is the status of the three crises in the history of mathematics?

I have seen a claim in some literature that there are three crises in the history of mathematics. The first is the discovery of $\sqrt2$ being irrational in Greek time which shook the belief that ...
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### Why do we call a linear mapping "linear mapping"?

According to P. M. Cohn's Classic Algebra, for historical reasons we call a linear mapping "linear mapping". What are the historical reasons that led to the adoption of the term "linear ...
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### Origin of "Spline" word

I was studying interpolation by Splines in numerical analysis and started to wonder the word's origin. I've found that it was a system used in technical drawings using weights but couldn't find why ...
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### What was Lebesgue's original definition of a measurable set?

I found an interesting question on Math SE asked by @Dilemian that seems more on topic here, and since it lacks answers there I thought to post it here so that it can receive good answers here. There ...
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### What was the definition of a scientist and how did it evolve? When was science categorized?

I'm asking this question as I've noticed that scientists like Gauss, Newton, Euler, Lagrange etc developed theories in many scientific fields(these ones that I know of were mostly interested in math ...
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### Who are "analysts" and "synthesists" in mathematics?

What is the difference between the terms "analysis" and "synthesis" used in a mathematical context? For example, Hawkins's Emergence of the Theory of Lie Groups p. 3 says that Klein and Lie were ...
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### History of the definition of Injective & Surjective Function

I'm a college student, just beginning to study Elementary Set Theory. In studying about the definition of injective and surjective function, out of curiosity, it came to my mind a question about the ...
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### Why is the existential quantifier symbol ∃ a backwards "E"?

Peano introduced a number of logical symbols still used today: $∨$ (from Latin vel) $∧$ (inverted $∨$) $∃$ This inversion of Latin letters as symbols (and inversion of symbols to signify their '...
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### Who invented the mole?

Who invented, or first used, the concept of the mole? I did my own research and the closest I came was Avogadro’s constant, which was made not by Avogadro but rather by Jean Baptiste Perrin. However, ...
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### What were the not-so-convincing reasons for using the word "power" for power sets?

A footnote of Enderton's Elements of Set Theory (1977, page 4) for the definition of power set states that the reasons for using the word "power" in this context are not very convincing, but the ...
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### Where did Master equations come from, and why are there so many of them?

The Wikipedia article about the Master equations describes pretty well how many there are and what kind of equations are called "Master equations". Does anyone know where the term originates, why ...
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### What is the history on the term 'co-domain'?

I am wondering if anyone knows any more on the history of the term 'co-domain' as it relates to functions. Two sources I found: Russell and Whitehead, Principia Mathematica, 1915, page 34 : the class ...
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### Why are canonical coordinates canonical?

Canonical coordinates are coordinates $q_i$ and $p_i$ in phase space that are used in the Hamiltonian formalism. The canonical coordinates satisfy the fundamental Poisson bracket relations: \...
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### When was the term "corollary" first used in proofs?

A dictionary search of the word "corollary" immediately yields the usual definition that all people involved with mathematics are used to dealing with. However, this surely comes from the Latin "...
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### Why is magnetic flux density named after Nikola Tesla?

I have my respect for Mr Tesla, but it seems weird that "he" was chosen to be the units of magnetic flux density. I mean, he didn't contribute much to magnetic fields theory, nor did he work ...
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### source of "logistic growth"?

I've been trying to find the source of the name of the DE modelling population growth known as logistic growth, for some time: why "Logistic" ? So far all my attempts to research it have hit dead ends ...
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### What does "given in species" mean in old geometry textbooks?

I recently came across the term "triangle given in species" in Hatton's Projective Geometry. Searching in archive.org turned up other examples (such as this) of 19th century texts, and it ...
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### Why do we call it a "positive definite matrix" rather than a "positively definite matrix"?

The term positive definite matrix is a standard one used in mathematics, especially in linear algebra. Are there grammatical, linguistic, or historical reasons why it was not called a positively ...
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### Was a mathematical connection involved when introducing "graph" of a function and "graph" in graph theory?

A colleague and I were having a discussion about mathematical similarities between graphs of functions and graphs as used in graph theory: Simple graphs can be defined in terms of pair (of vertices), ...
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### Why is the azimuthal quantum number so named?

The name "azimuthal quantum number" is often used for the total orbital angular momentum quantum number $\ell$ in an atom. What is the origin of this name? It makes no sense to me, since the usual ...
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### Why do English volume units use base 2?

I would post this on Quora, since it is more of a "just wondering" sort of question, except that I much prefer StackExchange's platform: As weird as Imperial units generally are, English volume units ...
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### What is the origin of the terminology 'spin up/down'?

In my research area one seminal reference is H. Bethe, ''Zur Theorie der Metalle'', Z. Phys. 71 205 (1931), see also the English translation by T. C. Dorlas (2009). On page 206 of the original ...
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### Where does the letter S in "$S$-units" and in localization $S^{-1} R$ come from?

In number theory, we may encounter the notion of $S$-unit, $S$-integer, etc. where $S$ is a finite set of prime numbers (for simplicity). For instance, if $S = \{2,3\}$ then the $S$-integers are the ...
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### When was the term 'elementary function' first coined and who did it?

The definition of what an elementary function is is quite arbitrary (see what math.SE has to say about it) and it makes me wonder why hasn't the mathematical community added other rather natural ...
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### Historical roots of the justification for the rule for multiplication of negative numbers

As a follow up question with respect to : Who wrote down minus times minus is equal to plus? and to : Historically, how did people define multiplication for negative numbers?, it can be interesting to ...
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### Why is the number of elements in a group called "order"?

This is a question that I have for a long time, Maybe it is something silly, but I really want to know. Why is the number of elements in a group called "order"? I mean, the word "order&...
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### What are the most famous examples of theory rebranding?

This question was sparked by the observation that the rebranding of the field called "neural networks" into "deep learning" is quite impressive. I wonder whether there have been similar renamings in ...
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### What is the origin of the term recombination?

During the introductory lecture to a cosmology course I'm currently taking, there was a brief discussion of some of the "highlights" of the Big Bang model. One of these is, of course, recombination. ...
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### How did the term "Michel electron" come about?

The Michel electron is what we call the electron produced from muon decay, and it's named after Louis Michel. I mention this in a paper I'm writing, and I was told that I need to cite it. I can't find ...
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### When were the abbreviations of chemical elements standardized?

This is going to be tricky because the discovery/synthesis of elements has taken place over centuries. It might be best to restrict this purely to the elements contained on Dmitri Mendeleyev's table, ...
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### How did the 'Poincaré patches' get their name?

De Sitter space and Anti de Sitter space are two of the most important solutions to the Einstein field equations. One famous method to obtain these spacetimes is to consider a $N$-dimensional ...
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### What is the name of this numeral system?

In a XVth century french manuscript on arithmetic and astrology, there is a description of a numeral system as follows (it starts here in the manuscript). Numbers between 1 and 9 are depicted by a ...
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### What is the etymology of the term space-time?

I'm looking for the earliest references to the word space-time (in the modern sense), in any language. The first references would likely be in German, as Raum-Zeit or Raumzeit. Of course, H. Minkowski ...
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