From Middle English experiment, from Old French esperiment (French expérience), from Latin experimentum, from experior ("to experience, to attempt"), itself from ex + *perior, in turn from Proto-Indo-European *per-.

• (British) IPA: /ɪkˈspɛɹ.ɪ.mənt/, /ɛkˈspɛɹ.ɪ.mənt/
• (America) IPA: /ɪkˈspɛɹ.ə.mənt/, /ɪkˈspɪɹ.ə.mənt/

experiment (plural experiments)

1. A test under controlled conditions made to either demonstrate a known truth, examine the validity of a hypothesis, or determine the efficacy or likelihood of something previously untried.

   conduct an experiment

   carry out some experiments

   perform a scientific experiment

   • 1837, L[etitia] E[lizabeth] L[andon], “The Laboratory”, in Ethel Churchill: Or, The Two Brides. […], volume II, London: Henry Colburn, […], →OCLC ↗, page 327 ↗:

     From her childhood she had been accustomed to watch, and often to aid, in her uncle's chemical experiments; she was, therefore, not at a loss, as a complete novice in the science would have been.

   • 2019, [https://web.archive.org/web/20190311070055/https://learningenglish.voanews.com/a/south-korea-proposes-rain-project-with-china-to-cut-pollution/4819207.html VOA Learning English] (public domain)

     South Korean officials announced last month that an experiment to create artificial rain did not provide the desired results.

2. (obsolete) Experience, practical familiarity with something.
   • 1590, Edmund Spenser, “Book II, Canto VI”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie, →OCLC ↗:

     Pilot [...] Vpon his card and compas firmes his eye,
     The maisters of his long experiment,
     And to them does the steddy helme apply [...].

• French: expérience
• German: Experiment, Versuch
• Italian: esperimento
• Portuguese: experimento (Brazil), experiência (Portugal)
• Russian: экспериме́нт
• Spanish: experimento

experiment (experiments, present participle experimenting; simple past and past participle experimented)

1. (intransitive) To conduct an experiment.

   We're going to experiment on rats.

2. (transitive, obsolete) To experience; to feel; to perceive; to detect.
   • 1662 Thomas Salusbury, Galileo's Dialogue Concerning the Two Chief World Systems (Dialogue 2):

     The Earth, the which may have carried us about perpetually ... without our being ever able to experiment its rest.

3. (transitive, obsolete) To test or ascertain by experiment; to try out; to make an experiment on.
   • 1481, The Mirrour of the World, William Caxton, 1.5.22:

     Til they had experimented whiche was trewe, and who knewe most.

• French: expérimenter
• German: experimentieren
• Italian: fare esperimento
• Portuguese: experimentar
• Russian: эксперименти́ровать
• Spanish: experimentar