'ready-sliced' originates from Modern English, specifically a compound of the adjective 'ready' and the past participle 'sliced' of the verb 'slice', where 'ready' meant 'prepared' and 'slice' meant 'to cut into thin pieces'.

'ready' comes from Old English words meaning 'prepared' and developed into the Modern English adjective 'ready'; 'slice' entered English via Middle English (influenced by Old French and/or Old Norse roots) and the past participle 'sliced' became commonly used to describe items already cut, forming compounds such as 'ready-sliced'.

Initially the components meant 'prepared' and 'to cut into pieces'; over time the compound came to be used specifically as an adjective meaning 'already cut into slices'.