Why was "tantrum" trending last week?
1640s, from sub- + marine (adj.).
"submarine boat," 1899, from submarine (adj.). The short form sub is first recorded 1917. Submarine sandwich (1955) so called from the shape of the roll.
hero sandwich • Also hoagy, torpedo, grinder, poor boy, etc depending on the locality
[1960s+; fr the shape of the bread cut lengthwise for the sandwich]