Definitionen
1.NounA strong seaward current; a riptide or undertow, especially as results when a sandbar formed by waves suddenly gives way, and which is dangerous to swimmers.
2.NounThe (flowing) channel which results when a cut is made (often deliberately by humans) in a barrier beach which separates a bay from an ocean, so as to control the water level in the bay (which affects water mills) and its salinity (which affects shellfish).
3.NounAlternative form of sea-purse (“egg case; sea bean”).