| Term | Definition |
| Antecedents | ancestors |
| Antedate | assign a date before the true date |
| Postdate | assign a date after the true date |
| Ante meridiem | before noon |
| Post meridiem | after noon |
| anteroom | waiting room |
| postgraduate | having to do with study after graduation |
| Postmortem | autopsy |
| Postscript | note added to a letter after it has been written |
| Bicameral | consisting of two chambers or legislative houses |
| Bicentennial | Two-hundreth anniversary |
| Biennial | occuring every two years |
| Semiannual | occuring every half year |
| Bimonthly | occuring every two months |
| semimonthly | occuring every half month |
| bilateral | having two sides |
| bilingual | written in two languages |
| bipartisan | representing two political parties |
| bisect | divide into two equal parts |
| semicircle | half of a circle |
| semiconscious | half conscious |
| semidetached | partly detached |
| semiskilled | partly skilled |