plural of periodical comet

plural of periodic comet

(astronomy) A comet which orbits the Sun and which returns to the innermost point of its orbit at known, regular intervals.

(rhetoric) A sentence whose main clause appears at its end.

A warm, dry postglacial interval.

plural of accounting period

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

A length of time in which the two sides to a purchase agreement, or contract can think things over and cancel with no penalty. This period is often stipulated by national law. In the UK it is currently (2008) 14 days. In many countries it is 10 days.

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.

plural of operational service period