I'm writing an academic paper in economics, and I'm using several different instantiations (I guess) of the Greek letter mu in several different mathematical equations. If I want to refer to all of them in my descriptive text, how should I do so? Should I write "mus"? Or "mu's"? Or should I insert the character itself, followed by just an "s"? Or followed by an " 's "?

  • 1
  • Do you intend to refer to the (literal) symbols or to the various concepts that may be represented by mu? If the latter, then there are no mus just several uses of mu in different contexts.
    – Fortiter
    Aug 8, 2013 at 0:59
  • The customary rules of forming plurals of an English word sare not suspended just because it should happen to be the name of a Greek letter. More than one alpha would be several alphas. More than one omega would be several omegas. I’m sure you can fill in the rest. :) And sigmata will just get you talked about. (:-!
    – tchrist
    Aug 8, 2013 at 3:14
  • alphas, betas, gammas, deltas, epsilons, zetas, etas, thetas, iotas, kappas, lambdas, mus, nus, xis, omicrons, pis, rhos, sigmas, taus, upsilons, phis, chis, psis, omegas.
    – tchrist
    Aug 8, 2013 at 3:21

3 Answers 3


Depending on context, you could perhaps refer to:

the characters (or symbols) µ

  • That sounds simpler than @CPLB's suggestion. Aug 7, 2013 at 21:56

"Mu" is the English name of the letter, so "mus" seems like an appropriate pluralisation.

From my experience, using the character itself with an s is not uncommon. I would not use an apostrophe as it is neither a contraction nor possessive, but a pair of inverted commas or quotation marks could be used for clarity. This could avoid the potential confusion of "s" also being a variable in your equations. (Although it is conventional for μ, as a quantity in an equation, to be italicised and the s, being text, to be roman).

As this is in the context of an academic paper featuring mathematics, I think the best solution would be to differentiating the different mus with a subscript, then you can define the set {μi} with i representing the possible subscripts. This approach is common within physics, although I cannot comment on other fields. It would also help your reader to disambiguate a particular instance of μ.


If you're referring to their use in equations, you can call them “the µ variables.”

Not the answer you're looking for? Browse other questions tagged or ask your own question.