'timber-built' originates from English, specifically the word 'timber' (from Old English 'timber', meaning 'wood for building' or 'building') and the past-participle form 'built' of the verb 'build' (from Old English 'byldan'/'buildan'), where 'timber' meant 'wood for building' and 'build' meant 'to construct'.

'timber' comes from Old English 'timber' (and from Proto-Germanic roots meaning 'building, material for building'), and 'built' is the past participle of Old English 'byldan'; the compound 'timber-built' arose in modern English by combining these elements to describe something constructed of timber.

Initially it referred directly to things made of timber ('wood for building'); over time the compound has remained stable in meaning and still denotes 'constructed of wood'.