seventeen-year-old

The compound "seventeen-year-old" is a modern English construction following a Germanic pattern for specifying age. Its first element, "seventeen," originates from the Old English 'seofontīene', a transparent compound meaning "seven-ten." The core components "year" and "old" are both fundamental, ancient Germanic words, with "year" (Old English 'gēar') relating to cycles of time and "old" (Old English 'eald') denoting duration of existence. The hyphenated structure emerged as a grammaticalized way to transform a simple age description ("seventeen years old") into a fixed, attributive adjective or a nominalized phrase, efficiently packaging the concept of a specific life stage into a single lexical unit.

Structure: seventeen + year + old - seventeen: From Old English 'seofontīene', a compound of 'seofon' (seven) and 'tīene' (ten). Its role is to denote the cardinal number 17. - year: From Old English 'gēar', meaning a period of twelve months. Its role is to specify the unit of time for the age. - old: From Old English 'eald', meaning having lived for a long time. Its role is to indicate the state of age.