'brick-built' is a compound of 'brick' + 'built'. 'brick' originates from Middle Dutch, specifically the word 'bricke', where it meant 'tile' or 'brick'. 'built' is the past participle of 'build', which comes from Old English 'byldan' (to build, construct).

'brick' passed into Middle English from Middle Dutch/Old French (e.g. Middle Dutch 'bricke', Old French 'brique') and kept its sense of a fired clay block; 'build' developed from Old English 'byldan' and the modern past participle 'built' reflects historical strong/weak verb changes and analogical forms.

Initially, 'brick' referred specifically to a tile or fired clay unit; over time it came to mean the building material 'brick' used in construction. 'Built' originally meant 'constructed' and has retained that meaning; 'brick-built' therefore came to mean 'constructed of bricks.'