Ab

noun4

1. •
   Symbol for antibody.
2. •
   (old-fashioned) In Egyptian belief, the heart and will and conscience of a person, especially that of the recently deceased which proceeds to the afterlife and is weighed as evidence during his or her judgement.
3. •
   (old-fashioned) An Ancient Egyptian amulet in the shape of a heart (ib).
4. •
   Abbreviation of Abbot.