the compound 'thrice-weekly' is a modern english formation that combines two distinct temporal elements. 'thrice' originates from the old english 'þrīwa', an adverbial form related to 'three', which itself descends from the proto-germanic 'þrīz' and ultimately the proto-indo-european 'tréyes'. 'weekly' derives from old english 'wīclīc', meaning 'of a week', with 'week' tracing back to proto-germanic 'wikōn', likely referring to a sequence or change. the compound's logic is transparently arithmetic, specifying an event's recurrence by multiplying the base unit of a week, a construction typical of english's analytical approach to denoting periodic intervals.

Structure: thrice + weekly - thrice: from middle english 'thries', from old english 'þrīwa', meaning 'three times'. functions as a quantifier. - weekly: from middle english 'wekely', from old english 'wīclīc', meaning 'of a week'. functions as an adjective/adverb suffix denoting frequency.