experiment (n.)

mid-14c., "action of observing or testing; an observation, test, or trial;" also "piece of evidence or empirical proof; feat of magic or sorcery," from Old French esperment "practical knowledge, cunning; enchantment, magic spell; trial, proof, example; lesson, sign, indication," from Latin experimentum "a trial, test, proof, experiment," noun of action from experiri "to try, test," from ex "out of" (see ex-) + peritus "experienced, tested," from PIE *per-yo-, suffixed form of root *per- (3) "to try, risk."

"make trial, operate (on something) so as to discover some unknown fact or to establish it when known," late 15c., from experiment (n.). Intransitive sense by 1787. Related: Experimented; experimenting.