Demi is a feminine given name and a surname. It may also refer to: Fictional characters Demi (Phantasy Star IV), female android from the video game Phantasy Star IV Demi Miller, in the BBC soap opera EastEnders Demi the Demoness, an underground comic book character Amounts demi (metric prefix) (or demi-), a former metric unit prefix not adopted by SI demi- (numerical prefix), a linguistic prefix representing half, see Numeral prefix "demi" (word), see List of Latin words with English derivatives "demi-" (medicine), see List of medical roots, suffixes and prefixes Other uses Demi (album), by Demi Lovato Demi River, Gujarat, India Short for demisexual, a sexual orientation Short for demigender, a gender identity See also Demy (disambiguation)