The term CA commonly means:
- California, a U.S. state
- Canada, a nation on the North American continent
- Chartered Accountant
- Compressed Air, such as "CA Piping"
- Certificate Authority
- Cyanoacrylate, a chemical compound
- See numerous other uses below, by category.
The term ca commonly means (more below):
- circa, as meaning approximately (ca.)
- .ca, Internet country code for Canada
The term Ca commonly means:
- Calcium, as a symbol for the chemical element (Ca)
The term cA commonly means:
- Centiampere, an SI unit of electric current (cA)