the compound adjective "weekend-long" is a modern formation following the productive english pattern of combining a noun with the adjective "long" to denote duration. the first element, "weekend," itself a compound from old english roots meaning "week" and "end," specifies the time period. the second element, "long," derives from proto-germanic langaz, meaning "long" in both spatial and temporal senses. the logic of the word is transparently descriptive, literally meaning "having the length of a weekend," and exemplifies how english readily creates new compound modifiers to express specific timeframes.

Structure: weekend (noun) + long (adjective) weekend: from old english wice (a turning, succession) and ende (end), combined to form a compound noun meaning the end of the week. long: from old english lang, long (having great linear extent, lasting a considerable time), functioning as an adjective.