1570s, "forming part of the accepted course of teaching," a sense now obsolete, from Latin magistralis "of a master," from magister "chief, director" (see master (n.)). Meaning "authoritative; of, pertaining to, or befitting a master" is from c. 1600. In pharmacy, of a remedy, etc., "devised by a physician for a particular case, prepared for the occasion" (c. 1600).
fem. proper name; from the name of the fertile coastal plain between Jaffa and Mount Carmel, from Hebrew, short for yesharon, properly "the Plain," from stem of yashar "was straight, was even" (compare Hebrew mishor "level land, plain"). A top-10 name for girls born in the U.S. between 1943 and 1949.
name given to various chronic skin diseases, later in more restricted use, 1530s, probably from leprous + -y (4). First used in Coverdale Bible, where it renders Hebrew cara'ath, which apparently was a comprehensive term for skin diseases. Also known as Hansen's disease (1938) for Norwegian physician Gerhard Henrik Armauer Hansen (1841-1912) who in 1871 discovered the bacillus that causes it.
The Middle English name for the disease was leper (mid-13c.), from Old French liepre and Latin lepra (see leper). But as the sense of this shifted after late 14c. to mean "person with leprosy," English began coining new nouns for the disease: lepri, leprosity, lepruse all date from mid-15c. but are now obsolete. A place for their treatment is a leprosarium (1846) or leprosary (1869, from French).
1958 as a colloquial shortening of progressive (q.v.). Earlier it was British student slang for proctor (1890) and earlier still a cant word for "food, provisions" (1650s), perhaps from verb prog "to poke about" (1610s), which is of unknown origin, perhaps related to prod (v.). Related: Progged; progging.