A periodical published in electronic format to be read on a computer or similar device.

plural of e-periodical

(astronomy) Taking over 200 years to complete an orbit; especially said of comets.

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

Pain felt in the abdomen during menstruation.

(communism, history) According to an obsolete theory, a period shortly after the Great Depression in which capitalism would be marked by further crises and then soon collapse.

A subdivision of the Devonian system of America

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

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

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