'Scaffold' traces to Latin 'fala' (siege tower) — a word for both builder's platform and executioner's stage.
A temporary structure of poles and planks used to support workers during the construction or repair of a building; also a raised platform used for public executions.
From Old North French 'escafaut' (scaffold, platform), a variant of Old French 'chafaut,' probably from Vulgar Latin *catafalicum, a compound of Latin 'cata-' (alongside, against) and 'fala' (siege tower, wooden tower). The word thus originally denoted a type of elevated wooden platform — a meaning that branched into both the builder's temporary working platform and the executioner's raised stage. The same Vulgar Latin root also produced 'catafalque' (a decorated platform for displaying a coffin at state funerals).
The word 'scaffold' and 'catafalque' (the platform for displaying coffins at state funerals) share the same Vulgar Latin ancestor *catafalicum. One word names the platform where buildings rise; the other names the platform where the dead are honored — both elevated stages for very different ceremonies.