A try-out is a period of testing something new to see whether it works well enough to keep. A shop gives a new till system a two-week try-out; a factory gives a machine a try-out before buying more. The idea is: use it for real, for a while, then decide. There is a second common meaning, especially in American English: a try-out is a test to see if a person is good enough to join a team, a play, or a music group. Actors go to try-outs for a part; students go to try-outs for the basketball team. In American English this is usually spelled tryout as one word, and it is very common in schools. Notice the hyphen and the stress: the noun try-out has its stress on TRY, while the verb phrase try out puts stress on OUT. They are the same idea in two shapes: you try out a new phone (verb), and that period is the try-out (noun).