ψ

Symbol



 * 1) Psychology.
 * 2) Psychiatry.
 * 3) Parapsychology, psychics.
 * 4)  A wavefunction.
 * 5)  Electric flux.
 * 6)  Water potential in cells.
 * 7)  Neptune.
 * 8)  asteroid (16)  (a stylized 𝜓)
 * 9)  The Psalms.
 * 10)  a voiceless retroflex click, IPA ⟨k͜𝼊⟩.
 * a voiced retroflex click, IPA ⟨ɡ͜𝼊⟩.
 * 1)  A bilabial trill, IPA ʙ|⟨ʙ⟩.

Usage notes
Some texts use Ψ (uppercase) for the actual wavefunction that appears in the time-dependent Schrödinger equation, and ψ (=ΨeiEt/ħ) (lowercase) for the time-independent spatial wave function that may exist for stationary states (and which then appears in the time-independent Schrödinger equation), but this distinction is not always observed. Otherwise, the distinction may be made by providing the arguments.

Etymology
Derived from its majuscule counterpart Ψ.

Letter

 * 1) Lower-case psi, the 23rd letter of the ancient Greek alphabet. It represented the consonant cluster  in the Eastern Greek alphabet and the voiceless aspirated velar plosive  in the Western Greek alphabet (compare Etruscan  khe). It is preceded by χ and followed by ω.

Derived terms
See also psi

Letter

 * 1) The lower case letter psi (ψι), the 23rd letter of the modern Greek alphabet.