| Abbreviation | Definition |
|---|---|
| APG | Association of Professional Genealogists |
| APGI | Association of Professional Genealogists in Ireland |
| APGQ | Association of Professional Genealogists Quarterly |
| API | Asian / Pacific Islander |
| APIG | Advanced Practical Internet Genealogy |
| APJG | Association of Professional Jewish Genealogists |
| APPONCLAM | Apponit Clamium |
| APPONCLAM | Apponit Clamium (he stands by, joins, or supports the claim) |
| AR | Anno Regni (Year of Reign) |
| ASG | American Society of Genealogists |
| ASGRA | Association of Scottish Genealogists and Researchers in Archives |
| B | Baptized |
| B. | Born (date/place of birth) |
| B. | Burial (location or date) |
| b. | date/place of birth |
| BAPT | Baptized |
| Bapt. | baptized |
| BART | Baronet |
| BEQ | Bequest |
| BET | Between |