definition
A submarine.
definition
A submarine sandwich: a sandwich made on a long bun.
example
We can get subs at that deli.
definition
A substitute, often in sports.
example
She worked as a sub until she got her teaching certificate.
definition
(often in plural) A subscription: a payment made for membership of a club, etc.
definition
A subtitle.
example
I've just noticed a mistake in the subs for this film.
definition
A subroutine (sometimes one that does not return a value, as distinguished from a function, which does).
definition
A subeditor.
definition
A subcontractor.
definition
(BDSM) A submissive.
definition
A subordinate.
definition
A subaltern.
definition
A subscription (or (by extension) a subscriber) to an online channel or feed.
example
I'm totally stoked; just got 10 new subs after my last video.
definition
Subsistence money: part of a worker's wages paid before the work is finished.