Write for Business - Blog

When a collective noun refers to a group as a unit, it is singular. (Use the singular pronoun its.)

The Advertising Department meets weekly. Its goal is to meet every day.
(group as a unit)

A collective noun that refers to a group's individual members is plural. (Use the plural pronoun their.)

The Advertising Department clapped their hands when their manager was introduced.
(group as individuals)

(From Write for Business, page 210, and Proofreader's Guide PDF, page 22)

The plurals of nouns ending with ful are formed by adding an s.

four cupfuls

six cupfuls

Note: When referring to separate cups full of something, use four cups full or six cups full.

(From Write for Business, page 210, and Proofreader's Guide PDF, page 22)

The plurals of nouns ending in f or fe are formed in one of two ways: If the final f sound is still heard in the plural form of the word, add only an s; if the final f sound becomes a v sound, change the f to ve and add s.

Plural ends with f sound:

proof - proofs; safe - safes

Plural ends with v sound:

shelf - shelves; life - lives

Plural ends with either sound:

scarf - scarfs, scarves

(From Write for Business, page 210, and Proofreader's Guide PDF, page 22)

The plurals of symbols, letters, numbers, and words discussed as words are formed by adding an apostrophe and an s.

Using &'s, @'s, and %'s in place of the words and, at, and percent will save room in this report. Don't forget to cross your t's. And, avoid using too many and's in your writing.

Note: It is permissible to omit the apostrophe when the omission does not cause confusion, but be consistent. Also, spelled-out numbers do not require an apostrophe.

DVD's or DVDs

fives and sixes

(From Write for Business, page 210, and Proofreader's Guide PDF, page 22)

The plurals of most nouns ending in an o that's preceded by a consonant are formed by adding es.

potato - potatoes

embargo - embargoes

soprano - sopranos

duo - duos

piano - pianos

Other exceptions include memos and nouns ending in o that can form plurals by adding either s or es, such as mementos/mementoes and cargos/cargoes.

(From Write for Business, page 209, and Proofreader's Guide PDF, page 21)