Real Dictionary

trial
If someone gives you a trial for a job, or if you are on trial, you do the job for a short period of time to see if you are suitable for it.
variable noun: A trial is a formal meeting in a law court, at which a judge and jury listen to evidence and decide whether a person is guilty of a crime.
variable noun: A trial is an experiment in which you test something by using it or doing it for a period of time to see how well it works. If something is on trial, it is being tested in this way.

trial in American English
of a trial or trials
the act or process of trying, testing, or putting to the proof; test
noun: the examination before a judicial tribunal of the facts put in issue in a cause, often including issues of law as well as those of fact

trial in British English 1
noun: the act or an instance of trying or proving; test or experiment

trial in British English 2
noun: a grammatical number occurring in some languages for words in contexts where exactly three of their referents are described or referred to