'breech' originates from Old English, specifically the word 'brēc,' where 'brēc' meant 'breeches or trousers.'

'brēc' changed from Old English word 'brēc' and eventually became the modern English word 'breech'.

Initially, it meant 'trousers or breeches,' but over time it evolved into its current meaning of 'the lower part of the body or the rear part of a firearm.'