PERIODIC; PERIODICAL a.
Happening, by revolution, at a stated time; returning regularly, after a certain period of time; acting, happening, or appearing, at fixed intervals; recurring; as, periodical epidemics. The periodic return of a plant's flowering. Henslow. To influence opinion through the periodical press. Courthope.…
PERMUTATION n.
terminate number of things, as units, objects, letters, etc., in all possible orders, one after the other; -- called also alternation. Cf. Combination, n., 4.
PEWTER n.
d, tough, but easily fusible, alloy, originally consisting of tin with a little lead, but afterwards modified by the addition of copper, antimony, or bismuth.
PHILOSOPHY n.
Literally, the love of, including the search after, wisdom; in actual usage, the knowledge of phenomena as explained by, and resolved into, causes and reasons, powers and laws.