Word Origin & History
c.1600, "kind of lobster," from sea + lion. Later "a fabulous animal" (in heraldry, etc.), 1660s. Applied from 1690s to various species of large eared seals. As code name for the planned Ger. invasion of Britain, it translates Ger. Seelöwe, announced by Hitler July 1940, scrubbed October 1940.