ea·gre also
ea·ger 
(
ēg
ər,
āg
ər)
n. Chiefly British See tidal bore.
[Early Modern English eagre, egre, ultimately (via Middle English *egre) from Old English *ēagor, ēgor (stem *ēaggr-), flood, water (attested in the poetic kennings ēgorhere, "water-host," deluge, and ēgorstrēam, "flood-stream," ocean); perhaps akin to Old English ēa, running water, stream, river, and īeg, island; see ISLAND.]