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

Any of certain species of cicadas, especially in genus Magicicada, which are known for their 17- and 13-year life-cycles, during most of which they develop underground, emerging in large numbers for a short time as large and audible adults, all those emerging in a year constituting a brood.

plural of periodical comet

plural of periodic comet

A regular period of time, as a month, quarter, or year, for which an operative statement is drawn up.

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

(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.