Alternative form of short-period comet

(mythology) In Arthurian legend, a vacant seat at the Round Table, reserved by Merlin for the knight who would one day be successful in the quest for the Holy Grail.

(mythology) Synonym of Siege Perilous

plural of periodic sentence

plural of period doubling

plural of periodical cicada

plural of perimeter fence

(psychology, biology) A maturational stage in the lifespan of an organism during which the nervous system is especially sensitive to certain environmental stimuli.

A time of warm climate in the North Atlantic region that may have been related to other climate events around the world during that time, and which lasted from about 950 to 1250.

(astronomy) The roughly 1460-year period of time between successive alignments of the first days of the Egyptian civil calendar and the observational Sothic year.