from Latin Curetes, from Greek Kouretes, plural of Koures, literally "youthful," related to koros "youth, child," male form of korē "maiden," from PIE *korwo- "growing" (hence "adolescent"), from suffixed form of root *ker- (2) "to grow."
"small boy," 1859, originally specifically one who does errands and chores for a gang of workmen (1851), perhaps from the canting sense "pickpocket, one who 'pinches' other people's property" (1530s; see nip (v.)). Nippers "pincer-like tool with cutting jaws," used by metal-workers, wire-drawers, etc., is from 1540s.
Meaning "pertaining to or suited to youth" is from 1660s. As a noun, "a young person," from 1733. Juvenile delinquency first recorded 1816; Juvenile delinquent the following year. Slang shortening juvie/juvey is recorded from 1941 as "juvenile delinquent," 1967 as "juvenile detention."
mid-15c., "youth, young person, one who is growing up," from French adolescent (15c.) or directly from Latin adolescentem/adulescentem (nominative adolescens/adulescens) "young man or woman, a youth," noun use of an adjective meaning "growing, near maturity, youthful," present participle of adolescere "grow up, come to maturity, ripen," from ad "to" (see ad-) + alescere "be nourished," hence, "increase, grow up," inchoative of alere "to nourish," from a suffixed form of PIE root *al- (2) "to grow, nourish." Adolesce was a back-formed verb used early 20c. (OED quotes H.G. Wells, G.B. Shaw, Louis MacNeice), but it seems not to have taken.
Islamic college, school for religious education of youth, 1620s, from Arabic madrasah, literally "a place of study," from locative prefix ma- + stem of darasa "he read repeatedly, he studied," which is related to Hebrew darash (compare midrash "biblical interpretation").