Definition of psi in English:


Pronunciation /sʌɪ//psʌɪ/


  • 1The twenty-third letter of the Greek alphabet (Ψ, ψ), transliterated as ‘ps’.

    • ‘Variable psi, used within the AHCPR guidelines, can help improve patient comfort.’
    • ‘Quantam has already certified a 10,000 psi tank, which in theory would double that.’
    • ‘Numbers one hundred to nine hundred: Rho, Sigma, Tau, Upsilon, Phi, Chi, Psi, Omega, Sampi.’
    • ‘Available in three sizes and able to pump up to a 160 psi max pressure, the pump will be available in September.’
    • ‘The psi / word association was randomly chosen to be either the first or second of these experiments.’
    • ‘However this may be replaced later in a few of the fleet cars by a 10,000 psi tank.’
    1. 1.1Astronomy followed by Latin genitive The twenty-third star in a constellation.
      ‘Psi Aquarii’
      • ‘In 1672, when Mars was in the vicinity of the three Psi stars of Aquarius, the time was ripe for obtaining the first reliable parallax of Mars.’
  • 2mass noun Supposed parapsychological or psychic faculties or phenomena.

    as modifier ‘psi powers’
    • ‘Is psi only a laboratory curiosity, or is it the universal connecting link among all of us?’