Compound noun and adjective

Compound nouns and compound adjectives are grouped together as they are constructed similarly and often originate from similar sources.

Compound nouns as a rule started out as adjectives or modifiers combined with nouns, such as "blackboard" originating from "black board"; "skyscraper" (sky modifying scraper - there are many types of scraper, this one metaphorically scraping the sky); "highlight" (high being adjective/modifier to light [meaning colour]); "temperance society" (temperance modifying society).
Although the left-hand (modifying) component often is an original noun, as a modifier it takes the function of an adjective for the main right-hand component.

So it is with compound adjectives as they are constructed in a very similar way to the compound noun. "Blackboard jungle", "leftover ingredients", "gunmetal sheen", "green monkey disease", are only a few examples.

Table of contents

1 Compound noun 1.1 The four types of compound noun 1.2 Rules of thumb 1.3 Left-hand modifiers of right-hand components 1.4 Sound patterns 1.5 Analyzability 1.6 Paraphrasing 1.7 Other languages 2 Compound adjective 2.8 Solid compound adjectives 2.9 Hyphenated compound adjectives

Compound noun

A compound noun usually consists of two or more free elements, morphemes that can stand on their own and that have their own meaning, but together form another word with a modified meaning.

In English, some grammarians call the right-hand component the head. The head is the categorical part that contains the basic meaning of the whole compound and the left-hand element modifies this.

The four types of compound noun

There are four types of compound nouns in English:

• the solid or closed form in which two, usually short, words appear together as one, such as "housewife", "lawsuit", "wallpaper". etc.
• the hyphenated form in which two or more words are connected by a hyphen, such as in "mother-of-pearl", "bridge-builder", "twenty-one", etc.
• the open or spaced form consisting of newer combinations of usually longer words, such as "distance learning", "player piano", "lawn tennis", etc.
• the classical type which consists of words derived from Latin, as in "horticulture", and those of Greek origin, as in "photography", the components of which are in bound form and cannot stand alone.

Rules of thumb

The way compound nouns are combined cannot always be strictly determined, and often a good dictionary may have to be consulted, but certain rules of thumb may be of use:

• Solid compounds most likely consist of short (single-syllable) units that often have been established in the language for a long time.
• Hyphenated compounds often have one component, a complex word, that has at least one or two affixes, such as "house-builder", "single-mindedness", etc.
• Open compounds usually consist of components which are not readily combinable in either solid or hyphenated forms, because they would either look strange in such a combination, or are of a recent coinage and have had not sufficient time to establish themselves in any other than open form.

Usage in the U.S. and in the UK differs and often depends on the individual choice of the writer rather than on a hard-and-fast rule, and so, open, hyphenated and closed forms may be encountered for the same compound noun, such as "container ship", "container-ship", or "containership"; "particle board", "particle-board", or "particleboard".

Left-hand modifiers of right-hand components

The left-hand component in a compound noun is the modifier, because it modifies or limits the meaning of the right-hand component. For example, in the solid compound "footstool", "foot" limits the meaning of "stool" to that of a "stool for one's foot or feet". (It can be used for sitting on but that is not its primary purpose). A "foundation stone" is a stone, one of a type and not of any other, with which a "foundation for a building is being laid".

A modifier in a compound fulfils a very similar function to that in an adjective + noun. A "black board" is any board that is black. A "blackboard", the compound, may have started out as any other "black board", but now is a thing that is constructed in a particular way, of a particular material and serves a particular purpose.

A modifier thus may indicate the purpose the noun stands for, the material of which it is made, or the way it works, is designed or constructed, as in "sand castle", "roundhouse", "workbench" or "particle-board".

Sound patterns

Another aspect, that of the sound pattern of compounds that originally started with an adjective modifier , ought to be considered. Sound patterns, such as stresses placed on particular syllables, may indicate whether the word group is a compound or whether it is an adjective + noun. A compound usually has a falling intonation such as "blackboard", the "White House", as opposed to the adjective and noun "black board", or "white house". (Note that this rule does not apply in all contexts. For example, the compound in "The White House announced a new policy today" and in comparisons the non-compound in "No, not the black house, the white house" are pronounced very similarly.)

Analyzability

Analyzability, too, is a means of arriving at the meaning of a compound word. Some, such as "lightweight" are easily analyzable, some others are less so, such as "steamboat", in which steam plays a certain role in the propulsion of the boat, but it is not clear how it does so, and thirdly those compounds that have as their components totally illogical and unanalyzable morphemes, such as "butterfly", "ladybird", "cranberry", etc. (A butterfly is neither connected to butter nor is it actually a fly).

Paraphrasing

A further aspect of compound nouns is that of the meaning being arrived at by paraphrasing the two morphemes through prepositions.

• A coffee pot is 'a pot for coffee'
• an office manager is 'a manager in an office'
• an armchair is 'a chair with arms'
• a raincoat is 'a coat against the rain'.

Other languages

Most natural languages have compound nouns and adjectives.

Spanish:

• rascacielos, rascar to scratch/scrape + cielos skies - skyscraper
• ciencia-ficción, ciencia science + ficción fiction - science-fiction
• ciempiés, cien hundred + pies feet - centipede
• ferrocarril, ferro iron + carril lane - railway

Italian

• grattacielo, grattare to scratch, scrape + cielo sky - skyscraper
• centopiedo, cento hundred + piedi feet - centipede
• ferrovia, ferro iron + via way - railway
• lavacristallo, lavare to wash + cristallo crystal, (pane of) glass - windscreen washer

French:

• gratte-ciel, gratte/gratter scratch/scrape + ciel sky - skyscraper
• chemin de fer, chemin way + de of + fer iron - railway
• moulin à vent, moulin mill + à by means of + vent wind - windmill
• grille-pain, griller to toast + pain bread - toaster

German:

• Wolkenkratzer, Wolke cloud + kratzer scraper - skyscraper
• Eisenbahn, Eisen iron + bahn track - railway
• Kraftfahrzeug, Kraft power + fahren/fahr drive + zeug machinery - car, automobile
• Stacheldraht, Stachel barb/barbed + draht'' wire - barbed wire

The longest compounds may be found in German such as the following:
Kontaktlinsenverträglichkeitstest - contact lens compatibility test
Rheindampfschiffahrtsgesellschaftskapitänsstellvertreter - Rhine steamship company vice captain.

Compound adjective

A compound adjective is a modifier of a noun. It consists of two or more morphemes of which the left-hand component limits or changes the modification of the right-hand one, as in "the dark-green dress", dark limits the green that modifies the dress.

Solid compound adjectives

There are some well-established permanent compound adjectives that have become solid over a longer period, especially in American usage: "earsplitting", "eyecatching", "downtown".
However in British usage these, apart from "downtown", are more likely written with a hyphen: "ear-splitting", "eye-catching".
Numbers that are spelled out and have the suffix -fold added: "fifteenfold", "sixfold".
Points of the compass: "northwest", "northwester", "northwesterly", "northwestwards", but not "North-West Frontier".

Hyphenated compound adjectives

A compound adjective should be hyphenated if the hyphen helps the reader differentiate a compound adjective from two adjacent adjectives that each independently modify the noun:
"old English scholar" - an old person who is English and a scholar, or an old scholar who studies English
"Old-English scholar" - a scholar of Old-English.
If, however, there is no risk of ambiguities, it may be written without a hyphen:
"Sunday morning walk".

Hyphenated compound adjectives may have been formed originally by an adjective preceding a noun:

• "round table" as in "round-table discussion"
• "blue sky" as in "blue-sky law"
• "red light" as in "red-light district"
• "four wheels" as in "four-wheel drive"

Others may have originated with a verb preceding an adjective or adverb:

• "feel good" as in "feel-good factor"
• "buy now", "pay later" as in "buy-now pay-later purchase"
  

and others were created with an original verb preceding a preposition

• "stick on" as in "stick-on label"
• "walk on" as in "walk-on part"
• "stand by" as in "stand-by fare"
• "roll on", "roll off" as in "roll-on roll-off ferry".

The following compound adjectives are always hyphenated:

An adjective preceding a noun to which -d or -ed has been added as a past participle construction:
"light-hearted banter",
"heavy-handed treatment",
"loud-mouthed yob",
"middle-aged lady",
"rose-tinted glasses".

A noun, adjective or adverb preceding a present participle:
"an awe-inspiring personality"
"a ground-breaking plan"
"a long-lasting affair"
"a far-reaching decision"

Numbers spelled out or as numerics:
"seven-year itch"
"five-sided polygon"
"20th-century poem"
"30-piece band"
"tenth-storey window"

A numeric with the affix -fold has a hyphen: "15-fold", but spelled out takes a solid construction: "tenfold".

Numbers, spelled out or numeric with added -odd:
"sixteen-odd"
"70-odd".

Compound adjectives with high- or low-:
"high-level discussion"
"low-price mark-up".

Colours in compounds:
"a dark-blue sweater"
"a reddish-orange dress".

Fractions as modifiers are hyphenated: "five-eighth inch", but if numerator or denominator are already hyphenated the fraction itself does not take a hyphen: "thirty-three thousandth part".

Comparatives and superlatives in compound adjectives also take hyphens:
"the highest-placed competitor"
"a shorter-term loan"
However a construction with most is not hyphenated:
"the most respected member".

Compounds including two geographical modifiers:
"Afro-Cuban"
"African-American"
"Anglo-Asian", but not "Central American".

The following compound adjectives are not normally hyphenated:

Where there is no risk of ambiguity:
"a Sunday morning walk".

Left-hand components of a compound adjective that end in -ly that modify right-hand components that are past participles (ending in -ed):
"a hotly disputed subject"
"a greatly improved scheme"
"a distantly related celebrity".

Compound adjectives that include comparatives and superlatives with more, most, less or least:
"a more recent development"
"the most respected member"
"a less opportune moment"
"the least expected event".

See also: Compound verb, Phrasal verb