ACT, the /ˌeɪ siː ˈtiː/ BrE AmE
1 . (the American Conservatory Theater) a ↑ repertory theatre (=theatre whose actors perform different plays on different days) in San Francisco, which is also a respected school for training actors
2 . (the Australian Capital Territory) the CAPITAL TERRITORY of Australia. It contains the CAPITAL CITY Canberra and is an ↑ inland area surrounded by New South Wales.