See also: Def. and def English English Wikipedia has an article on:DEFWikipedia Noun DEF (countable and uncountable, plural DEFs) (automotive) Abbreviation of diesel exhaust fluid. (roleplaying games) Initialism of defence point. (broadcasting) Initialism of daily electronic feed. (broadcasting) Initialism of delayed electronic feed. Anagrams DfE, FDE, FED, Fed, Fed., f***ed, fedRemove adsWikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads