(idiomatic, slang, euphemistic) Menstruating.

plural of period of time

plural of time period

(historical) The Uruk period.

(historical) A period between circa 4000 to 3100 BC which saw the emergence of urban life in Mesopotamia and the Sumerian civilization.

(UK, television) A period of time on a Saturday during which football matches may not be broadcast (so as to avoid reduced attendance in person at other football matches that are not being televised).

plural of closed period

A work of art or drama which evokes a particular historical era. / A work which evokes the era in which it was produced, but may not have any other especial features.

the average interval between fertilization and birth of a mammal; ranges from 13 days for the opossum to 626 days for the Indian elephant

(astronomy) Synonym of non-periodic