early 14c., "symbolization, representation," from Old French significacion and directly from Latin significationem (nominative significatio) "a signifying, indication, expression, sign, token, meaning, emphasis," noun of action from past participle stem of significare "make known, indicate" (see signify). From late 14c. as "meaning" (of a word, etc.). Old English used getacnung as a loan-translation of Latin significatio.
child's name for a horse, also a toy horse or rocking horse, 1540s, a nursery word of uncertain signification.
short for rhinoceros, 1884. As slang for "cash" (also rino) 1680s, but the signification is now unknown. Hence cant rhinocerial "rich."
also pet-cock, "a small plug-cock, made to be fastened to a pipe and used for draining water and condensation from steam cylinders, etc.," 1864, from cock (n.2); the signification of the first element is uncertain.