Rule 8.2: Use hyphens to connect words that are directly related

What a checker looks for

Usually a deviation, and context can excuse it.

• Flag a multi-word adjectival phrase directly before a noun that functions as a single modifier but lacks a hyphen (e.g. 'low altitude flight', 'quick release fastener').
• Flag a two-word number or fraction written without a hyphen (e.g. 'forty seven', 'three sixteenths').
• Flag a term combining an uppercase letter or a number with a noun to describe a shape or configuration that lacks a hyphen (e.g. 'L shaped bracket', '3 prong connector').
• Flag a compound verb formed from a noun (or other part of speech) plus a verb that lacks a hyphen (e.g. 'heat treat', 'jump start').
• Flag a term where a prefix ending in a vowel is joined to a root word starting with a vowel but lacks a hyphen (e.g. 'preamplifier', 'deicing', 'antiicing', 'preengage' should be 'pre-amplifier', 'de-icing', 'anti-icing', 'pre-engage').

What this rule does not cover

• A dash — a longer mark used to divide ideas, show a range, or signal a pause — is a different punctuation mark from the hyphen and is not covered by this rule.

How to fix it

Insert a hyphen between the directly related words to form the compound term, following the pattern that applies (compound adjective before a noun, two-word number, letter/number-plus-noun shape term, noun-derived verb, or vowel-ending-prefix plus vowel-starting root).

Constraints on the fix

• Only hyphenate words that are genuinely directly related; do not hyphenate unrelated adjacent words.
• Do not turn a hyphen into a dash or a dash into a hyphen.