Meaning of “trial” - Learner’s Dictionary

trial

noun [ C, U ] uk us /traɪəl/
LAW

B2 a legal process to decide if someone is guilty of a crime:

The two men are now on trial for attempted murder.
He will be taken to the US to stand trial.
TEST

a test of something new to find out if it is safe, works correctly, etc:

trial and error

a way of learning the best way to do something by trying different methods:

There aren't any instructions with it - it's just a matter of trial and error.

(Definition of “trial” from the Cambridge Learner’s Dictionary © Cambridge University Press)