A compound of turn + coat, reportedly derived from the sometime military practice of wearing uniform coats that were lined in material of a contrasting color, and which could be worn inside out to present a different appearance.
Pronunciation
Lua error in Module:parameters at line 291: Parameter 1 should be a valid language or etymology language code; the value "UK" is not valid. See WT:LOL and WT:LOL/E.IPA(key): /ˈtəːn.kəʊt/
Lua error in Module:parameters at line 291: Parameter 1 should be a valid language or etymology language code; the value "US" is not valid. See WT:LOL and WT:LOL/E.IPA(key): /ˈtɝn.koʊt/