Wheelhouse
“Wheelhouses,” so sayeth Wiktionary, “are the small enclosed parts of a bridge which historically held the ship’s steering wheel”.
By extension of stone dead metaphor, one’s wheelhouse is one’s area of interest, competence or preference — ones bag, baby—articulated in a way that only an American would not respond to with a roundhouse slap upside the head.
Known in sailing circles as a cockpit, which is a much better name for the place where you would find the sort of gent who uses the expression “wheelhouse”.
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