-A dolphin; a porpoise.
From Middle English mereswin (“porpoise, dolphin”), from Old English mereswīn (“porpoise, dolphin”), from Proto-Germanic *mariswīną (“dolphin, porpoise, cetacean”) from Proto-Germanic *mari (“sea”) + Proto-Germanic *swīną (“swine, pig”), equivalent to mer- + swine.
So, in short, it means “Sea Pig”.
Used in a sentence:
“The obscure legend of the camelopard and the mereswine is the most tragic love story I’ve ever heard outside of the Jerry Springer Show.”
We have a lovely mereswine T-shirt available!