| ACA | a school for special training |
|---|---|
| ACA | a secondary school (usually private) |
| ACA | an institution for the advancement of art or science or literature |
| ACA | the French-speaking part of the Canadian Maritime Provinces |
| ACA | a national park in Maine showing marine erosion and glaciation |
| ACA | an early French settler in the Maritimes |
| ACA | a genus of herbs and shrubs belonging to the family Euphorbiaceae |
| ACA | weedy herb of eastern North America |
| ACA | widely distributed herbs and shrubs and trees |
| ACA | the craniometric point at the anterior extremity of the intermaxillary suture |
| ACA | a genus of Xenicidae |
| ACA | small green-and-bronze bird |