(of an astronomic object) The time taken to rotate about its axis relative to the background stars.

rotational period

A relatively brief period when a new leader is given greater leeway with respect to changes he or she wishes to make.

A period during which a new employee is monitored to assess his/her capability.

plural of period piece

(epidemiology) The time elapsed between an exposure to a pathogenic organism, a chemical or radiation, and the appearance of signs and symptoms.

An event of a woman's discharging of menstrual flow of blood and cells.

Alternative form of menstrual period

(grammar) A sentence whose main clause appears at the end, after other, especially dependent, clauses. / (physics) A structure made of bays coupled through one or more coordinates.

(Britain, informal, plural only) Underwear worn by a woman or girl during menstruation, typically old, cheap, or of a dark colour in case of staining.