1 test, trial, investigation, inquiry or enquiry, examination, experimentation, research, proof:
Experiment has shown that the ointment cures many minor skin ailments.
2 procedure, policy:
Totalitarianism seems to have failed as a political experiment.
3 experiment on or with. test, try, examine, investigate, research, probe:
The time has come to experiment on human subjects. Artists now experiment with many media, from canvas to computers.