- (physics) a waveform in Quantum Physics and is used in various forms of the Schrödinger Equation.
- (electrical engineering) Electric flux.
ψ • (ps) (lowercase, uppercase Ψ)
- The lower case letter psi (ψι), the 23rd letter of the modern Greek alphabet.
- The number 700 in Greek numerals.
- The number 700,000 in Greek numerals.