Of a vessel: to roll so far on its side that it cannot recover; to capsize or turn turtle.
To collapse in a faint; to black out, to swoon.
To die.
To capture a turtle by turning it onto its back.
Especially of a boat or ship, or some other vehicle: to turn upside down.
To roll upside down with one's surfboard (usually a longboard) to allow a wave, especially a wave that has already broken, to pass over.
To fail; to go belly up.