'crust' originates from Latin, specifically the word 'crusta', where 'crusta' meant 'hard outer covering'.

'crust' changed from Old French word 'cruste' and Middle English form 'crust(e)' and eventually became the modern English word 'crust'.

Initially, it meant 'a hard outer layer', and over time it has retained that core meaning while extending to verbal senses like 'to form a crust'.