something that people do or cause to happen
"The new law requires every citizen to take an active part in community service as a mandatory act of civic duty."
a subdivision of a play or opera or ballet
"The audience waited anxiously for the third act to begin after two hours of performances."
An instance of a certain standardized college admissions test in the United States, originally called the American College Test.
"His greatest act was sacrificing his own safety to save the stranger."
Something done, a deed.
In plain English: An act is something you do on purpose, especially when it follows from your thoughts or feelings.
"The manager thanked everyone for their hard work and positive act during the crisis."
be engaged in an activity, often for no particular purpose other than pleasure
"The children spent the afternoon acting around the backyard, pretending to be pirates without any real game planned."
To do something.
"Please act quickly to help the person who is injured."
Initialism of Australian Capital Territory, a federal territory of Australia.
"Residents across ACT enjoy access to many cultural and recreational facilities within the region."
The word "act" comes from the Latin verb agere, meaning "to do." It originally referred to a register of events or a decree before entering Middle and Old English.