sea adder
nounEtymology From sea + adder. Compare Old English mere-næddra (“sea-adder, lamprey”).
1
A European fifteen-spined stickleback, a fish of species Spinachia spinachia (syn. Gasterosteus spinachia).
2
A tanglefish, or greater pipefish (Syngnathus acus).
3
Obsolete A sea serpent.