What are "Compound Words"? -- A compound word consists of two or more base words. Meaning of Compound word is often different from the separate base words. Compound Words and Parts of Speech Compound words are mostly nouns, adjectives, and verbs. Kinds of Compound Words Compound words are of three types: A. Closed Compound Words: Words are joined together. There is no space or hyphen between the words. Examples: firefly / softball / redhead / keyboard / makeup / notebook. B. Hyphenated Compound Words: Words are joined together by a hyphen. Examples: daughter-in-law / over-the-counter / six-year-old C. Open Compound Words: Words are not joined together. Words are open or separate. In other words, there is a space between the words. Examples: post office / real estate / full moon / half sister Some general rules regarding use of hyphens: Compound Adjectives are often hyphenated-- If compound adjective precedes a noun, they are hyphenated -- low-paying job low- paying is a compound adjective; job is a noun]; good-looking celebrity good-looking is a compound adjective; celebrity is a noun] Adverbs that end in -ly and compounded with another modifier are not hyphenated: quietly organized meeting / highly placed sources . Also note: 1. Some compound words which are hyphenated in American English are not hyphenated in British English. Example: cash-back American English]; cashback British English] 2. Some compound words may have more than one form but these forms may belong to different parts of speech. Examples: bread and butter open form] noun], bread-and-butter closed form] adjective]; charge sheet open form] noun], chargesheet closed form] verb]; fast track open form] noun], fast-track hyphenated form] adjective, verb]; first degree open form] noun], first-degree hyphenated form] adjective]; full time open form] noun], full-time hyphenated form] adjective, adverb]; gift wrap open form] noun], gift-wrap hyphenated form] verb]; hard core open form] noun], hard-core hyphenated form] adjective]; hard line open form] noun], hard-line hyphenated form] adjective]; road test open form] noun], road-test hyphenated form] verb]; second hand open form] noun], second-home hyphenated form] adjective]; Formation of Compound Words- Compound Words Are Formed In The Following Ways: A. Compound words with adjective and adjective: adjective + adjective bittersweet / blue-black / red-hot / white-hot B. Compound words with adjective and noun: adjective + noun- blackboard / black man / bluebird / common room / concrete idea / deep-sea / electric light / fool play / free trade / full-length / high school / hot water / last-minute / loudspeaker / low-key / madman / midday / monthly ticket / nobleman / old boy / poorhouse / red heart / shorthand / smallpox / stronghold / sweetheart / wild boar / widespread C. Compound words with adjective and verb: adjective + verb - broadcast / clear-cut / dry-clean / fulfill / safeguard / whitewash D. Compound words with adjective and past participle: adjective + past participle - cold-blooded / kindhearted / long-haired / long forgotten / old-fashioned / short-sighted / well-known / well-mannered E. Compound words with adjective and present participle: adjective + present participle - free-standing / good-looking / hardworking / long-lasting / speed walking (F). Compound words with adverb (or preposition) and adjective: adverb (or preposition) + adjective - ingrown / over wide / under ripe G. Compound words with adverb (or preposition) and noun: adverb (or preposition) + noun - afterlife / afterthought / background / backdate / bypass / downstairs / downfall / forehead / foresight / in-group / in-service / inside / offshore / offspring / off-shoot / online / outlaw / outpatient / over change / overcharge / overripe / overdose / overnight / overweight / underground / underline / underworld / upgrade / upstairs