decades-long

the compound adjective "decades-long" is a modern english formation built from two native elements. the first part, "decade," entered english via middle french from late latin "decas," which itself originated from greek "dekas," meaning a group of ten, specifically ten years. the second element, "long," is a fundamental germanic word from old english "lang," denoting extensive duration. the compounding logic is transparent and analogical, following the pattern of other duration adjectives like "hours-long" or "centuries-long." it directly combines the plural measure of time with the enduring quality to create a single descriptive term for phenomena spanning multiple ten-year periods.

Structure: decades (plural of decade) + long (lasting) - decades: from latin 'decas', from greek 'dekas' (a group of ten), via old french. in english, it functions as the plural noun meaning periods of ten years. - long: from old english 'lang, long' (having great linear extent, lasting a great while), of germanic origin. in this compound, it functions as an adjective meaning having a specified duration.