'saddlebag' originates from English, specifically from the combination of 'saddle' and 'bag', where 'saddle' referred to the seat for a rider on an animal and 'bag' meant a container for carrying items.

'saddlebag' was formed in English by compounding the words 'saddle' and 'bag' in the 18th century, and it has remained in use in its current form.

Initially, it meant 'a bag attached to a saddle for carrying items', and this meaning has largely remained the same in modern usage.