Definition of "phi" in English

noun

1. Φ, the 21st letter of the Euclidean and modern Greek alphabet, usually romanized as "ph".

2. (mathematics) The golden ratio.

3. A visual illusion whereby a sequential pattern of lights produces a false sense of motion.

   • […] tolerance (Frenkel-Brunswik 1949) for it showed that those persons with the strongest defences against internal conflict, i.e. obsessionals and conversion hysterics, were those least able to perceive the reality-conflicting phenomenon of phi.