Webster's Revised Unabridged Dictionary · 1913

Capsize

Capsize , verb, transitive and intransitive

[Compare Sp. cabecear to nod, pitch, capuzar, chapuzar, to sink (a vessel) by the head; both from Latin caput head.]

To upset or overturn, as a vessel or other body.
But what if carrying sail capsize the boat? — Byron

Capsize , noun

An upset or overturn.