»plurale tantum

From Wikipedia: A plurale tantum (plural: pluralia tantum) is a noun that appears only in the plural form and does not have a singular variant, though it may still refer to one or many of the objects it names. Many languages have pluralia tantum, such as the English words "scissors" and "pants", or the Swedish word inälvor "intestines".

Something I have always wanted to know, but never actually did know. Also: The plural of plurale tantum is pluralia tantum.

I found also: Mass noun. I came across these terms while sorting out whether "ox-tail" refers to meat from the same species of animal as "beef" (bos taurus, although I once ate aurochs, and now discover that they were part of an unsettling "back-breeding" scheme). "Cattle" is an example of a word in plural only, with no singular.