capsize (v.)

"to turn over, overturn," 1780 (transitive); 1792 (intransitive), a nautical word of obscure origin, perhaps (as Skeat suggests) from Spanish capuzar "to sink by the head," from cabo "head," from Latin caput "head" (from PIE root *kaput- "head"). For sense, compare French chavirer "to capsize, upset," faire capot "capsize;" Provençal cap virar "to turn the head." Related: Capsized; capsizing.