a school period in which a student has free time, i.e., is not enrolled in a class.

plural of personality cult

Alternative form of cult of personality

Alternative form of perf

plural of key performance indicator

Aphredoderus sayanus, a North American freshwater fish of family Aphredoderidae: order Percopsiformes.

plural of perfect metal

(Scientology) A person who is seen in Scientology as having an "antisocial" personality, due to leaving the Church or other causes.

(chemistry, obsolete) Any metal, such as gold or silver, not readily oxidized by heat and air.

(physics) Half of the period of a wave etc; typically the time taken for part of a wave to be replaced by a similar part that is out of phase.