Is mother a collective noun?

Unless I'm missing something here, no. A collective noun is something like flock, congregation, or skein (not of wool). It's a grouping of other things. Mothers tend to be individuals. And before anyone suggests it, 'charity worker' is not a collective noun. Even when they're rattling a tin at you...

A rattle of charity workers perhaps?
Cheers, DaveJ

Frank Zappa and the Mothers of Invention.

That's more than one mother...

A GAGGLE of geese. A POD of whales. A MURDER of crows.


Collective nouns (also known as terms of venery or nouns of assemblage) in English are subject-specific words used to define a grouping of people, animals, objects or concepts. For example, in the phrase "a parliament of owls", parliament is a collective noun.

http://www.grammar-monster.com/glossary/collective_nouns.htm

Most of these collective nouns were invented by Victorian parsons and such with nothing better to do. No-one uses them outside crosswords and quizzes. Gaggle and skein, yes, pod and some others. But a murmuration of larks? Have you ever SEEN a group of larks? I haven't. Nor a group of owls. There's even one for rhinoceroses - which are extremely solitary beasts! In the UK at least, if you see a flock of crows, they're probably rooks anyway...

Correction - an exultation of larks. They still don't group round here.

C. S. Lewis refered to a parliament of owls in his Chronicles of Narnia, I believe...

Mother of all wars.

That is descriptive or categoric not collective.