sub

Etymology 1

Shortened form of any of various words beginning with sub-.

noun

1. Abbreviation of submarine.
   You know, we got Russian subs creepin' around; anythin' goes wrong they can say whatever they want happened! Give their folks medals! 1989, James Cameron, The Abyss (motion picture), spoken by Alan "Hippy" Carnes (Todd Graff)
2. Short for submarine sandwich.: a sandwich made on a long bun.
   We can get subs at that deli.
3. (nautical) A submersible
4. (informal) Clipping of substitute., often in sports or teaching.
   With the score 4 to 1, they brought in subs.
   She worked as a sub until she got her teaching certificate.
   At any other school you would be playing varsity, and Wallace has you pigeon-holed on the subs." "Maybe he has his reasons," Jim replied. "And he hasn't pigeon-holed me on the subs yet — not this season. 1930, Boy's Live, Philip Scruggs, There Can Be Victory, page 20
5. (Britain, informal, often in plural) A subscription: a payment made for membership of a club, etc.
   According to the best available information, GALAXY has several times as many subs as any other science fiction magazine! 1951, H. L. Gold, “Annual Report”, in Galaxy Science Fiction, volume 2, number 6, page 2
6. (Internet, informal) A subtitle.
   I've just noticed a mistake in the subs for this film.
7. (computing, programming) A subroutine (sometimes one that does not return a value, as distinguished from a function, which does).
   The default accessor can be overridden by declaring a sub of the same name in the package. 2002, Nathan Patwardhan, Ellen Siever, Stephen Spainhour, Perl in a nutshell
   So far, all the subs and functions that we have used have been those built into the system, or those written to handle events from controls […] 2004, P. K. McBride, Introductory Visual Basic.NET, page 49
8. (colloquial) A subeditor.
9. (colloquial) A subcontractor.
10. (slang) A subwoofer.
11. (publishing, colloquial) A submission (of a work for publication).
12. (BDSM, informal) A submissive.
    […] roleplay where a sub or bottom takes care of a top's bodily and hygiene needs […] 2004, Paul Baker, Fantabulosa: A Dictionary of Polari and Gay Slang
    "It means that I'm both a sub and a dom." "Submissive and dominant," I said. He nodded. 2007, Laurell K Hamilton, The Harlequin
    Typically a dom and a sub have a more or less standard routine that they like to go through all the time. 2008, Lannie Rose, How to Change Your Sex
13. (colloquial, dated) A subordinate.
14. (colloquial, dated) A subaltern.
    He was known as 'Mad Carew' by the subs at Khatmandu, He was hotter than they felt inclined to tell; But for all his foolish pranks, he was worshipped in the ranks, And the Colonel's daughter smiled on him as well. 1911, J. Milton Hayes, The Green Eye of the Yellow God
15. (colloquial, Internet) 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.
16. (colloquial) Subsistence money: part of a worker's wages paid before the work is finished.
17. (Internet slang) Short for subreddit.

verb

1. (US, informal) To substitute for.
2. (US, informal) To work as a substitute teacher, especially in primary and secondary education.
3. (Britain, informal, soccer) 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. (Britain, informal, soccer) 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. (Britain) To perform the work of a subeditor or copy editor; to subedit.
6. (slang, Internet, transitive) To subtitle (usually a film or television program).
7. (UK, slang, transitive) To lend.
   I kept up the pleasantries as we were drying our hands and, realizing I didn't have any change for the lodger, I asked him, one drummer to another like, if he could sub me a quid for the dish. 2011, Rowland Rivron, What the F*** Did I Do Last Night?
8. (slang, intransitive) To subscribe.
9. (BDSM) To take a submissive role.
   You've never subbed before. Jessica will be expecting a man on stage that follows orders and enjoys what she's going to be doing. Do you want to be spanked? Possibly whipped? 2012, Alicia White, Jessica's Breakdown, page 53
   Wasn't like she'd never subbed before. She'd been a sub longer than she'd been a Dominatrix–ten years she'd spent in a collar. 2012, Tiffany Reisz, Little Red Riding Crop

Etymology 2

From Latin sub.

prep

1. Under.

verb

1. To coat with a layer of adhering material; to planarize by means of such a coating.
2. (microscopy) To prepare (a slide) with a layer of transparent substance to support and/or fix the sample.
   1997, Marina A. Lynch, S. M. O'Mara (editors), Ali D. Hames, D. Rickwood (series editors), Neuroscience Labfax, page 166, Ensure that gloves are worn when handling subbed slides. Although the following protocol describes subbing with gelatin, slides may also be coated with either 3-(triethoxysilyl-)propylamine (TESPA) or poly-L-lysine for in situ hybridization.