The Remedy of the Week: Plurals of compound nouns

Each week proofreader Hannah Jones discusses and offers a remedy to common problems we encounter when writing. Today she gives advice on how to form the plurals of compound nouns.

Why is it grown-ups but runners-up? What is the plural of Poet Laureate? Why is it all so confusing? These are all questions I have asked myself while writing or proofreading. As always, there are no hard-and-fast rules, but here are some general guidelines on how to form the plurals of those pesky compound nouns.

What is a compound noun?

A compound noun consists of two or more words which function together as a single noun. Compound nouns may be closed (a single word with no spaces or hyphens), open (with spaces between the words), or hyphenated.

Types of compound noun
Closed compounds Open compounds Hyphenated compounds
bookshelf Bachelor's degree copy-editor
proofreader head teacher daughter-in-law
businesswoman Poet Laureate master-at-arms

Forming the plural

Closed compounds

Closed compounds are pluralised by forming the plural of the last component, e.g. ‘shelf’ in ‘bookshelf’:


Open compounds

In open compounds, the key word (or the most significant one) is pluralised, e.g. ‘Poet’ in ‘Poet Laureate’:

Bachelor’s degrees
head teachers
Poets Laureate

Hyphenated compounds

Similarly the plural of a hyphenated compound is formed by pluralising the key word, e.g. ‘editor’ in ‘copy-editor’:


When a noun is hyphenated with a preposition, the noun is pluralised, e.g. ‘hanger’ in ‘hanger-on’:


However, if neither part of the compound is a noun, the final word is pluralised, e.g. ‘between’ in ‘go-between’:


The remedy

The most important thing to remember is that the principle word takes the plural. If you are unsure, it is always worth referring to a dictionary. Sometimes you will find two options listed; for instance, the New Oxford Dictionary for Writers & Editors lists both 'Poets Laureate' and 'Poet Laureates' as acceptable. Choose whichever sounds best to you or consult your style guide (if applicable).

No matter what, just make sure you use the same form consistently throughout!

Further reading

For more information on when to use hyphens, see my blog post on the subject.

Hannah Jones is a professional freelance proofreader and owner of The Remedy of Errors.

Visit her website at The Remedy of Errors. She can also be found on Twitter @remedyoferrorsFacebook and LinkedIn.