(informal) abdominal muscle.

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

(climbing, informal) To abseil. / Abbreviation of abort.

Abbreviation of abortion.

Abbreviation of about.

Abbreviation of about.

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

Abbreviation of Alberta, a province of Canada. / Initialism of Artium baccalaureus.

Initialism of able seaman; able-bodied seaman. / Initialism of adult baby. / Initialism of afterburner. / Initialism of aid to the blind. / (military, aviation) Initialism of airbase.

Initialism of airborne. / Initialism of antiballistic. / (baseball) Initialism of at bat.