1670s, "pertaining to a system," from French systématique or directly from Late Latin systematicus, from Greek systematikos "combined in a whole," from systema (genitive systematos); see system. From 1789 as "methodical," often in a bad sense, "ruthlessly methodical." Related: Systematical (1660s); systematically.
"made shut, not open," c. 1200, past-participle adjective from close (v.). Closed circuit "complete, unbroken (electrical) circuit" is attested from 1827; closed shop"workplace in which only union members are employed" is from 1904; closed system first recorded 1896 in William James as "complete and unalterable system (of doctrines, etc.)." Later used in a physical sense, "system in which the total mass or energy remains constant."