Hyphenated two-word modifiers

Do not hyphenate two-word modifiers that are chemical names (e.g., amino acid level, barium sulfate precipitate). 

When two or more two-word modifiers have the same base (the second word in the modifier), and modify the same noun, use a hyphen after each modifier, without repeating the base ... 

Hyphenate unit modifiers containing three words when similar two-word modifiers are hyphenated. 

Do not hyphenate unit modifiers containing three or more words, even if similar two-word modifiers are hyphenated, when doing so would break other rules. For example, do not hyphenate unit modifiers if one of the words is a proper name. Do not hyphenate unit modifiers that are two-word chemical names. 

Two- and three-word modifiers (often requiring the use of hyphens) are common in titles because they can make the title more concise. The hyphenated words may be used in the X, Y, and/or Z parts of the title, as illustrated below. (Note, too, that none of these titles begin with the word The. )... 

There are many types of two-word modihers (noun + adjective, adjective -i- noun, noun + noun), but almost all are hyphenated when used to modify a noun (see table A4). 

Read the following sentences, all taken from the chemical literature but with most hyphens removed. Locate two- or three-word modifiers. Decide if they require hyphens. Add hyphens where necessary. If the sentence has no two- or three-word modifiers, write correct as is . 

Hyphenate the suffix like in two-word compounds used as unit modifiers. 

Unit modifiers are two words that together describe a noun they are almost always hyphenated. Most unit modifiers consist of... 

The suffix like . Hyphenate the suffix like to words of three or more syllables, to two-word compounds used as unit modifiers, to chemical names, and to proper nouns and adjectives. 

When two or more unit modifiers with the same ending base (a word or unit of measure) modify one noun, use a hyphen after each element, and do not repeat the ending base. 

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