'quay' originates from Middle English, specifically the word 'quai', which came via Old Norman/Old French from Middle Dutch 'kade' (also 'kaai') meaning 'shore' or 'bank'.

'quay' changed from Middle Dutch 'kade'/'kaai' and Old Norman/Old French forms into Middle English 'quai' and eventually became the modern English word 'quay'.

Initially, it referred to a 'bank' or 'shore structure' (a place at the water's edge); over time it evolved into the current sense of a constructed platform or wharf where ships load and unload.