sub

1. A submarine.
2. A submarine sandwich: a sandwich made on a long bun.

   We can get subs at that deli.

3. A substitute, often in sports.

   She worked as a sub until she got her teaching certificate.

4. (often in plural) A subscription: a payment made for membership of a club, etc.
5. A subtitle.

   I've just noticed a mistake in the subs for this film.

6. A subroutine (sometimes one that does not return a value, as distinguished from a function, which does).
7. A subeditor.
8. A subcontractor.
9. (BDSM) A submissive.
10. A subordinate.
11. A subaltern.
12. A subscription (or (by extension) a subscriber) to an online channel or feed.

    I'm totally stoked; just got 10 new subs after my last video.

13. Subsistence money: part of a worker's wages paid before the work is finished.

1. To substitute for.
2. To work as a substitute teacher, especially in primary and secondary education.
3. To replace (a player) with a substitute.

   He never really made a contribution to the match, so it was no surprise when he was subbed at half time.

4. Less commonly, and often as sub on, to bring on (a player) as a substitute.

   He was subbed on half way through the second half, and scored within minutes.

5. To perform the work of a subeditor or copy editor; to subedit.
6. To lend.
7. To subscribe.
8. (BDSM) To take a submissive role.

1. To coat with a layer of adhering material; to planarize by means of such a coating.
2. To prepare (a slide) with a layer of transparent substance to support and/or fix the sample.

preposition

Under.