| apotheosis | The highest point in the development of something; a culmination or climax | |
| appease | To bring peace, quiet, or calm to; soothe | |
| apportion | Divide and allocate | |
| apposite | Apt in the circumstances or in relation to something | |
| approbation | Approval or praise, often in an official sense | |
| apropos | With reference to; concerning | |
| arbitrary | Based on random choice or personal whim, rather than any reason or system | |
| arcane | Understood by few; mysterious or secret | |
| arch | a curved symmetrical structure spanning an opening and typically supporting the weight of a bridge, roof, or wall above | |
| archaic | very old or old-fashioned | |