Noun
A worldly sailor.
Synonym: barnacle
A sailor who has crossed the equator.
Source: en.wiktionary.orgAnd when they leave — you don’t just get up and walk out of Shellback; you get up to see Rico and say goodbye,” Partelow said. Source: Internet
Shellback sits at the bottom of Manhattan Beach Boulevard, positioned like a flipper in a pinball machine that stops those who might be inclined to bounce down toward the sand. Source: Internet