Definition of "ψ"

Psychology.  examples

Psychiatry.  examples

Parapsychology, psychics.  examples

(quantum mechanics) A wavefunction.  examples

(electrical engineering) Electric flux.  examples

(physics, biochemistry) Water potential in cells.  examples

(astrology, dated) Neptune.

(astrology, italic) asteroid (16) Psyche (a stylized 𝜓)

(Christianity) The Psalms (a book in the Bible).  examples

(phonetics, dated) a voiceless retroflex click, IPA ⟨𝼊⟩.  examples