English Pronunciation Audio (US):(file) Noun horse armor (plural horse armors) Used other than figuratively or idiomatically: see horse, armor.; armor worn by a horse. (idiomatic, humorous, chiefly derogatory, gaming, Internet slang) A piece of downloadable content or microtransaction for a video game, especially one purely cosmetic and considered being of bad value.Wikiwand - on Seamless Wikipedia browsing. On steroids.