1640s, "one who schemes or plots;" agent noun from design (v.). In manufacturing or the fine arts, "one who makes an artistic design or a construction plan" is from 1660s. In fashion, as an adjective, "bearing the label of a famous clothing designer" (thus presumed to be expensive or prestigious), from 1966. Designer drug, one that mimics an illegal narcotic but has a different chemical composition so as to avoid legal restrictions, is attested by 1983.
late 15c., from Latin interior "inner, interior, middle," comparative adjective of inter "within" (from PIE *enter "between, among," comparative of root *en "in"). Specific meaning "away from the coast, of the interior parts of a country" is from 1777. Interior decoration first attested 1769; interior decorator is from 1830. Interior design from 1927.
"part of a country distant from the coast," 1796, from interior (adj.); meaning "internal part, inside" is from 1828. Meaning "internal affairs of a country or state" (as in U.S. Department of the Interior) is from 1826. The Latin adjective also was used as a noun.
descriptive of a dress or skirt flared in shape of a capital letter "A," 1955, in reference to the creations of French fashion designer Christian Dior (1905-1957).
capital of Oman, from Arabic Masqat, said to mean "hidden" (it is isolated from the interior by hills).