(military, historical) A proposed but unadopted air-officer rank of the Royal Air Force equivalent to air vice-marshal.

(organic chemistry) The organometallic aromatic anion [(2Z)-penta-2,4-dienylidene]chromium or any of its derivatives

A substance to be dissolved.

(fandom slang) An object sought by a character in a story in order to achieve some objective, having little purpose beyond advancing the plot.