periodical

& s. [Eng. periodic; -al.] A. As adjective: 1. Pertaining to a period or periods, or to division by periods. "The squares of the periodical times of all the satellites belonging to each planet."- Herschel . Astronomy , § 533. 2. Performed in a period or regular revolution; proceeding in a series of succe ive circuits. periosteum 6. Pertaining to or connected with a periodical or publication appearing at regular intervals; as, a magazine, . B. As subst.: A publication, as a magazine, review, or newspaper, which appears at regular intervals. "These periodicals seem to be intended for boys from twelve to sixteen years of age." - Scribner's Magazine, March, 1878, p. 684. periodical-comets, s. pl. Astron.: Comets returning at fixed periods. periodical-diseases, s. pl. Pathol.: Diseases of which the paroxysms or other changes recur at stated intervals, sometimes lunar periods. periodical-meteors, s. pl. Astron.: Meteors entering the earth's atmosphere at stated periods of the year. [METEOR.] IMG:content-0900.png:[blocks in formation]