| Abbreviation | Definition |
|---|---|
| A | Acre |
| AAGRA | Australasian Association of Genealogists and Record Agents |
| AAS | American Antiquarian Society |
| AAS | Anno Aetatis Suae (Died in the year of (his/her) age) |
| ACC | ACCording to .... |
| ACKD | Acknowledged |
| ADMR | Administrator |
| ADMX | Administratrix |
| ADS | AD Sectam (at the suit of ....) |
| AET | Aetatis (about the age of ....) |
| AFN | Ancestral File Number |
| AG | Accredited Genealogist |
| AG | American Genealogy |
| AG:ABC | American Genealogy: A Basic Course |
| AGRA | Association of Genealogists and Record Agents |
| AH | Aunts Husband |
| AIHA | Australian-Irish Heritage Association |
| ALD | ALDerman |
| AM | Anno Mundi (year of the world) |
| AMHS | Alberta Métis Historical Society |