'slip-on' originates from the English verb 'slip,' meaning 'to move smoothly or easily,' combined with 'on,' indicating the action of putting something on.

'Slip-on' evolved from the concept of 'slip' in Middle English, which meant 'to glide or move smoothly,' and was combined with 'on' to describe clothing or shoes that could be easily worn.

Initially, it referred to the action of slipping something on easily, and this meaning has largely remained the same in modern usage.