The word 'teenaged' is a modern English formation that directly builds upon the concept of the 'teen' years. Its core component, 'teen', originates from the Old English word for 'ten', which forms the second element of the numbers thirteen through nineteen. This morpheme was abstracted to collectively refer to that specific decade of life. Combined with 'age', denoting a period or state of being, and the adjectival suffix '-d', the term literally constructs the meaning "being in the state of the teen years." It is a transparent, descriptive compound that logically connects the numerical root to a specific life stage.

Structure: teen (ten) + age (state, period) + d (adjective suffix) - teen: From Old English tēne, tīen, from Proto-Germanic tehun, meaning "ten". In this word, it refers to the numbers thirteen to nineteen. - age: From Old French aage, eage, from Vulgar Latin aetāticum, from Latin aetās (age, period of life). It denotes a state, period, or condition. - d: A common English suffix used to form adjectives from nouns or other adjectives, indicating possession of a quality.