Definition of placebo in English:


Line breaks: pla|cebo
Pronunciation: /pləˈsiːbəʊ

noun (plural placebos)

  • 1A medicine or procedure prescribed for the psychological benefit to the patient rather than for any physiological effect.
    More example sentences
    • According to the report published in the British Medical Journal, 60 percent of medical professionals prescribe placebos to their patients.
    • According to a new study by Israeli researchers, most doctors prescribe placebos to their patients, and in most of these cases, the patients are told they are receiving real medication.
    • And, if some patients benefit from placebos, and they are not harmed, I guess I can live with that.
  • 1.1A substance that has no therapeutic effect, used as a control in testing new drugs.
    More example sentences
    • All placebo controlled trials were positive and all comparative trials indicated equivalence with other active therapies.
    • That one doesn't get answered as often as it should, because the FDA generally only requires testing against placebo.
    • The practice of testing new medicines against placebo, rather than against the best treatment available, has contributed to a general lack of knowledge.
  • 1.2A measure designed merely to humour or placate someone: pacified by the placebos of the previous year, they claimed a moral victory
    More example sentences
    • It's interesting that the broken crosswalk buttons were not originally designed to act as placebos (presumably).
    • The stock markets, leisure travel, and all the other industries affected are relying on the sum of all these measures, including the placebos, to recover.
    • There is some debate as to whether an argon suit inflation system keeps you warm, or merely acts as a placebo i.e. making you believe that you're warmer!


late 18th century: from Latin, literally 'I shall be acceptable or pleasing', from placere 'to please'.

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