What is the Plural of ‘Series’?

The plural of series is simply series. It is an invariant noun, meaning the spelling stays the same for both singular and ...
THE WEEK

11 nouns that only have a plural form

Of all the grammar concepts we have, "plural" seems to be one of the most straightforward. You got one thing? It's singular. Got more than one thing? It's plural. But alas, language is always less ...
The Guardian

Why do some English words have the same singular and plural? Examples are mostly animals - deer, fish, moose, sheep, swine, buffalo - but also aircraft, stone (weight), head ...

Could it be that these are animals that were hunted, fished, or herded and that there was a convention that used the singular as a sort of generic plural when going after these creatures for sport or ...
The New York Times

The Plural of E-Mail

Ashley Mergen asks: "What is the proper plural of e-mail? When referring to snail mail, you would not say, 'I received a hundred mails,' but rather, 'I received a hundred pieces of mail' or 'I ...
The New York Times

ARE OR IS?; Whether a Plural or a Singular Verb Goes With the Words United States.

Written for THE NEW YORK TIMES SATUR- DAY REVIEW By the Hon. John W. Foster. Formerly Secretary of State, United States Minister To Russia, Spain, &C. TimesMachine is an exclusive benefit for home ...