hyphens in compound nouns

Free grammar tips, lessons and tests

Recommended purchases

This site: Grammar Monster on line Daily tips with Grammar Monster's gadget Daily tips with Grammar Monster on Twitter  The best grammar reference books Grammar Monster off line The only grammar checker we'll endorse
Common grammar errors
Easily confused words
Grammar terms & definitions
Grammar tests
Grammar lessons
Search this site


 Home

Search
 

Glossary
of Terms

Common
Errors

FAQs

Grammar
Chat

Download

Grammar
Checker


 
For things that are described using two words (e.g., cooking-oil), there is sometimes a requirement to use a hyphen to eliminate ambiguity.
 


Use a Hyphen to Eliminate Ambiguity

There are no specific rules on forming compound nouns. For example, 'Ink-well' can be also be written 'ink well' or 'inkwell' - all are correct spellings. However, you should use a hyphen to eliminate ambiguity. Ambiguity is particularly prevalent when the first word of the pairing is a substance (like 'water' or 'ink').

Examples:

water-bottle / water bottle
(When the first word is a substance, a hyphen is used to show that the item is 
not made of that substance.) 

ice-axe / ice axe
(Both are acceptable, but 'ice-axe' makes it clear that the axe is not made of ice.)

paper-clip / paper clip / paperclip
(All 3 are acceptable. However, if the clip were made of paper, then only
'paper clip' could be used.)

Please could you pass me that plastic wire-fastener?
(a fastener made of plastic, i.e., not wire)

There is also some ambiguity when the first word of the pairing ends 'ing'. (This is called a present participle.)

Examples:

changing-room / changing room
(Both are acceptable, but 'changing-room' makes it clear that the room is not
changing.)

laughing-gas / laughing gas
(Both are acceptable, but 'laughing-gas' makes it clear that the gas is not
laughing.)   
COMPOUND NOUN?

A single noun that comprises two or more words is called a 'compound noun'. Sometimes the words in a compound noun are joined together by a hyphen or hyphens. (e.g., water-bottle) (See lesson Types of Nouns.)
NOT ALL HAVE A ONE-WORD VERSION 

Be aware that not all compound nouns have a one-word version. Even though 'inkwell' and 'paperclip' are fine, 'iceaxe' and 'waterbottle' are spelling mistakes. There are no rules governing this - you have to know.  
Associated lessons:
 
What are nouns?
The different types of nouns
Alternatives to hyphens in compound adjectives
Hyphens in compound adjectives
Hyphens in prefixes
 
 

Grammar Monster © | Copyright Registration Number: 226604 | All rights reserved