ab

Etymology 1

Abbreviation of abdominal muscles.

noun

1. (informal) abdominal muscle.
   The bikinied models in most of the ESPN2 shows have abs. Many of the malnourished bikinied models in the commercials have visible rib cages. How did the two get conflated into a shared vision of beauty? 2006, H. Peter Steeves, The Things Themselves, page 75
   When possible, do your ab workout on a day when you're not training a major muscle group […] . 2010, Bill Geiger, "6-pack Abs in 9 Weeks", Reps! 17:106

Etymology 2

Abbreviation of abscess.

noun

1. (slang) An abscess caused by injecting an illegal drug, usually heroin.

Etymology 3

Abbreviations.

verb

1. (climbing, informal) To abseil.
   I had a climbing rope in my pack, set up an abseil with it, and abbed down to him. 1998, Climbing, numbers 178-180, page 22
2. Abbreviation of abort.

noun

1. Abbreviation of abortion.

prep

1. Abbreviation of about.

adv

1. Abbreviation of about.

Etymology 4

From the spelling books and the fact that it was the first of the letter combinations.

noun

1. (US) The early stages of; the beginning process; the start.