Likely derived from bulge.
- (nautical) The rounded portion of a ship's hull, forming a transition between the bottom and the sides.
- (nautical) The lowest inner part of a ship's hull, where water accumulates.
- (uncountable) The water accumulated in the bilge, the bilge water.
- (slang, uncountable) Stupid talk or writing; nonsense.
- The bulging part of a barrel or cask.
- (nautical, intransitive) To spring a leak in the bilge.
- (intransitive) To bulge or swell.
- (nautical, transitive) To break open the bilge(s) of.
From Old Turkic 𐰋𐰃𐰠𐰏𐰀 (bilge, “wise”), from 𐰋𐰃𐰠 (bil-, “to know”) + 𐰏𐰀 (-ge). Compare bil- (“to know”). Fallen into disuse since the 15th century, but revived in 1935 in the campaign by the Türk Dil Kurumu to replace many loanwords by words with native Turkic roots.