psi

or p.s.i.


pounds per square inch.

Definition for psi (2 of 3)

psi1
[ sahy, psahy ]
/ saɪ, psaɪ /

noun, plural psis.

the 23rd letter of the Greek alphabet (Ψ, ψ).
the group of consonant sounds represented by this letter.

Origin of psi

1
1350–1400; Middle English < Greek pseî

Definition for psi (3 of 3)

psi2
[ sahy ]
/ saɪ /

noun

any purportedly psychic phenomenon, as psychokinesis, telepathy, clairvoyance, or the like.

Origin of psi

2
1940–45; shortening of psychic or parapsychic
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for psi

British Dictionary definitions for psi (1 of 2)

psi1

abbreviation for

pounds per square inch

British Dictionary definitions for psi (2 of 2)

psi2
/ (psaɪ) /

noun

the 23rd letter of the Greek alphabet (Ψ, ψ), a composite consonant, transliterated as ps
  1. paranormal or psychic phenomena collectively
  2. (as modifier)psi powers
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for psi

psi
[ sī, psī ]

n.

The 23rd letter of the Greek alphabet.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.