seven-year-old

The compound "seven-year-old" is a modern English construction built from three fundamental Germanic elements. "Seven" descends from an ancient and stable Indo-European numeral, while "year" originates from a root meaning a seasonal cycle or period. The adjective "old" stems from a root conveying growth and maturity. When combined in the hyphenated pattern common to age descriptors in English, these morphemes create a precise and formulaic term. Its logic is transparently compositional, directly stating the count of annual cycles lived to define a specific stage of age, whether applied adjectivally or nominally.

Structure: seven (number) + year (time unit) + old (age) - seven: From Old English seofon, from Proto-Germanic sebun, from Proto-Indo-European septḿ̥. Functions as a cardinal number. - year: From Old English ġēar, from Proto-Germanic jērą, from Proto-Indo-European yóh₁r̥. Functions as a noun denoting a time period. - old: From Old English eald, from Proto-Germanic aldaz, from Proto-Indo-European h₂eltós. Functions as an adjective describing age.