2.02 Compound nouns and nouns in compounds

(a) Hyphenate two nouns representing different but equally important functions, i.e. where the hyphen denotes the relationship "both A and B":

• city-state
• comedy-ballet
• dinner-dance
• soldier-statesman
• tractor-trailer
• writer-editor

(b) Hyphenate nouns normally written as two words, when they have a modifier and when ambiguity would otherwise result:

• colour filter but red colour-filter
• letter writers but public letter-writers

Similarly, compound nouns normally written as a single word must be separated into their component parts and then joined to their modifier by a hyphen when the modifier applies only to the first component:

• ironworker but structural-iron worker
• housekeeper but lodging-house keeper

(c) Hyphenate compound units of measurement made by combining single units that stand in a mathematical relationship to each other:

• car-miles
• kilowatt-hours
• light-year
• person-day

(d) Hyphenate compounds that include a finite verb:

• a has-been
• a stay-at-home
• a sing-along
• a stick-in-the-mud
• a Johnny-come-lately
• a ne’er-do-well

(e) Hyphenate nouns of family relationship formed with great and in-law:

• mother-in-law
• great-grandfather

but

• foster father
• half sister
• stepson
• godmother

2.03 Nouns with adjectives and participles

(a) Hyphenate noun-plus-adjective compounds (in that order), whether used attributively or predicatively:

• duty-free goods
  • The goods were duty-free.
• tax-exempt bonds
  • The bonds are tax-exempt.

(b) Hyphenate noun-plus-participle compounds regardless of the position:

• snow-capped mountains
  • The mountains are snow-capped.
• a time-consuming activity
  • This activity is time-consuming.

Hyphenate noun-plus-participle compounds, Exceptions

There are a number of them, including handmade and handwritten.

(c) Do not hyphenate noun-plus-gerund compounds (present participle used as a noun); they may be written as one or as separate words:

• decision making
• power sharing
• problem solving
• deficit spending

• housekeeping
• shipbuilding
• sightseeing
• cabinetmaking

Do not hyphenate noun-plus-gerund compounds, Exceptions

• foot-dragging
• gut-wrenching

See 2.04 Compound adjectives; adjectives and participles in compounds(e) for such compounds used adjectivally.

© Services publics et Approvisionnement Canada, 2024
TERMIUM Plus^®, la banque de données terminologiques et linguistiques du gouvernement du Canada
Outils d'aide à la rédaction – The Canadian Style
Un produit du Bureau de la traduction