half-mast, half-staff – Flags fly at half-mast on ships and at Naval stations on shore. Elsewhere on shore, flags fly at half-staff.
hangar, hanger – A hangar is an enclosed space, such as those for aircraft repair and storage. A hanger is something that hangs, such as a clothes hanger.
hashtag – The use of a number or hash sign (#) in a tweet to convey the subject a user is writing about so that it can be indexed and accessed in other users’ feeds. If someone is writing about the Super Bowl, for example, #superbowl could be an appropriate hashtag. There is no space between the hashtag and the accompanying search term. Hashtags are sometimes used on social networks other than Twitter, such as Instagram.
homefront – One word.
homepage – One word.
hotline – No hyphen.
House of Representatives – Capitalize only when referring to a specific government body: The U.S. House of Representatives, the Pennsylvania House of Representatives.
Humvee – This is the trademark for the four-wheeled vehicle that AM General Motors built (HMMWV –high-mobility multipurpose wheeled vehicle).
hurricane – Capitalize as part of the name forecasters give to a storm: Hurricane Andrew. But use only it and its in pronoun references. Lowercase in plural uses: hurricanes Andrew and Katrina.
husband, wife – Husband or wife is acceptable in all references to individuals in any legally recognized marriage. It is acceptable to use spouse or partner is acceptable on request or to be gender-neutral. Use same-sex couple or partner, when applicable, when developing web content. When referring to the policy, use official terminology: same-sex domestic partner. In direct quotes, regardless of sexual orientation, husband or wife is acceptable in all references to individuals in any legally recognized marriage. Spouse or partner is acceptable to use on request.