ad

Etymology 1

Clipping of advertise, advertising, advertisement, advertiser.

noun

1. Abbreviation of advertisement.
   I have placed both of the ads in the newspaper as instructed.
2. Abbreviation of advertising.
3. Abbreviation of advertiser.

Etymology 2

From a shortening of the word advantage.

noun

1. (tennis) Advantage; also, designating the left-hand side, from the player's point of view, of their half of the court, where the advantage point following a deuce is always played.
   [S]uddenly Agassi hits a hard heavy cross-court back hand that pulls Federer way out to his ad (= his left) side, and Federer gets to it but slices the stretch backhand short, a couple feet past the service line […]. 2006, David Foster Wallace, “Federer Both Flesh And Not”, in Both Flesh And Not, Penguin, published 2013, page 5
2. (debating) advantage
   ads and disads

Etymology 3

From Latin ad (“to, on”).

prep

1. to, toward