Groups, Rings and Fields. I am asking for the analogy behind these structures names. Why is a "field" called a field? Is there an analogy between a usual ring (finger ring) and a mathematical ring?
 A: From mathoverflow. Source at the end.
Why is a ring called "a ring"?

The idea that the name is motivated by 'circling back' might or might
  not be true. But I could not find any trace of it there. In
  particular, there seems to be no result close by regarding the fact
  that the powers αn somehow 'circle back' to linear combinations (the
  idea mentioned by KConrad); also no analogy to rings of residue
  classes is drawn. (Of course, it is proved somewhere that such a
  'ring' has a finite Z-module basis but the way this is presented does
  not suggest any particular 'circling back' idea.)
Hilbert's definition for ring is (paraphrasing): given a collection of
  algebraic integers, a ring is everything that can be written as
  polynomial functions with integer coefficients of this given
  collection. (As an aside, personally, I now finally understood the
  idea behind the name integral domain/'Integritätsbereich'; a number
  field is also called 'Rationalitätsbereich', so rational domain there,
  being everything one gets with rational functions and the integral
  domain is what one gets with integral functions. Added: I saw had I
  started to read MO earlier I could have learned this usage due to
  Kronecker was mentioned by KConrad on the question linked to).
He then right away comments that a 'ring' is thus closed/invariant
  under addition, subtraction, and multiplication.
So, perhaps it is a ring just since one does not leave it even if one
  moves around, say like a boxing-ring. Or, I quite like the idea
  presented earlier of 'Ring' also being used to describe (figuratively)
  a collection of people with a certain relation among them, a property
  this word shares with 'Gruppe' [group] and also 'Körper' [field, but
  literally body], both seem to have been established by then already.
  (Which also is somehow a partial response to why a ring is a ring even
  though it is not more ring-like than a group or a field; the later two
  already had a different name.)
Then, it seems the first axiomatisation of some notion of ring is due
  to Fraenkel (J. Reine Angew. Math., 1915). I stress some notion, since
  it does not completely match current practise in that each element is
  either a zero-divisor or invertible (and while non-commuativity is
  allowed it is only in a somewhat restricted sense in that the two
  products must only differ by an invertible element). The guiding
  example seems to be rings of integers modulo composites.
Regarding the name 'Ring' (that paper is also in German) he credits
  Hilbert but says there is some deviation of the meaning.
By constrast, Steinitz in his earlier axiomatization of fields (J.
  Reine Angew. Math., 1910) also discusses 'Integritätsbereiche'
  (integral domains) with exatly the axiomatization common today. (comm.
  ring, with unit, no zero-divisors).
Then to 'Moderne Algebra' (1930) by van der Waerden (based on lectures
  by Artin and Noether). [To be precise, I could not look at the
  original edition, but only some later edition, I hope this did not
  change over time.]
There one finds 'Ring' defined, (essentially) as is done now, as a
  basic notion; without any discussion of the naming. [To be precise, a
  ring there has not necessarily a multiplicative unit element and the
  existence of additive inverse and neutral element is expressed
  together via imposing solubility of a+X=b for all a,b.]
In addition, one also finds 'Integritätsbereich' there with a
  different meaning than 'Ring'; namely as commutaitve ring without
  zero-divisors (yet not necessarily with unit element, so somewhat
  deviating from current usage and Steinitz).
I think one can make an argument that the structure is now called ring
  because it is called like that in 'Moderne Algebra', and one can note
  that also the naming of integral domain survived. (Except for slight
  deviation with unit element, but which until today is not quite
  uniform.)
And, it seems reasonable to assume that the naming of Artin, Noether,
  van der Waerden as for Franekel is directly inspired by Hilbert. After
  all, a ring has (just) the main properties mentioned by Hilbert for
  his 'rings', closed under addition, subtraction, and multiplication.
  What I do not know is whether there is any earlier axiomatization of
  ring in (or at least closer than Fraenkel's to) the current sense.
  Fraenkel's
To sum it up, this is all but a 'definite' answer, but I hope it
  contains some relevant information. In my opinion, it could be
  difficult, possibly even impossible, to ascertain what precisely
  motivated the choice of name and even more so to really pin down why
  one name survived and another not (say, Integritätsbereich did,
  Rationalitätsbereich did not). It could however be interesting to
  research literature and in particular lecture notes, if existant, of
  the beginning 20th century to see the development in more detail.
Still, ring seems like a good word as there are some potential
  intuitions (this circling back and the residue classes), also it is
  short and was I think quite different from preexisting names.

Source: https://mathoverflow.net/questions/117292/why-is-a-ring-called-a-ring
A: I have long wondered about the use of the term "field" in algebra.  Here is what I have learned.
The original term for such a structure, due to Dedekind, is "Zahlenkörper", which is German for "body of numbers"; it is now usually shortened to "Körper".  Several other European languages use analogous terms for the same algebraic structure; e.g. "corps" in French and "cuerpo" in Spanish.  Another early term, no longer in use, was Kronecker's "Rationalitaetsbereich", which means something like "realm of rationalities".
Wikipedia suggests the earliest use of the term "field" in English was due to E.H. Moore in 1893, but I recall seeing a usage by H.J.S. Smith, who died a decade earlier (I have, unfortunately, lost the reference).  It is not clear why "field" (which is indeed a possible rendering of "Bereich") was used instead of "body".
A number of languages now use terms that correspond to the English "field"; e.g. "поле" in Russian and "campo" in Italian.
