(historical) The history of Japan covering the years from AD 710 to 794. Empress Gemmei established the capital of Heijō-kyō (present-day Nara).

Sexual intercourse during menstruation.

(education) A high school class that is offered early in the morning, before the scheduled start of the school day.

(astronomy) The apparent orbital period of a planet as seen from Earth.

(astronomy) sidereal orbital period / (astronomy) sidereal rotation period

(history) The age of mass migration of Germanic people in Europe during the early Middle Ages, circa 376 to 800 AD.

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

(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.

Time period between the receipt of the letter of dismissal and the last working day.

plural of accounting period