psi Hear it!

psi1 definition

psi (sī, psē)

noun

the twenty-third letter of the Greek alphabet (Ψ, ψ)

Etymology: LGr < Gr psei

psi2 definition

psi (sī)

adjective

of or having to do with psychic or paranormal abilities or phenomena

noun

such abilities or phenomena collectively
psi3 definition

psi

pounds per square inch

Webster's New World College Dictionary Copyright © 2009 by Wiley Publishing, Inc., Cleveland, Ohio.
Used by arrangement with John Wiley & Sons, Inc.

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