'stud' originates from Old English, specifically the word 'stod', where 'stod' meant 'a herd of horses' or 'place of breeding'.

'stud' changed from Old English 'stod' into Middle English forms such as 'stud' meaning a place for breeding horses; the sense of a fixed projecting object or decorative fastener developed later by extension from items fixed into place.

Initially, it meant 'herd or place of breeding horses', but over time it expanded to mean 'a place for breeding', and later broadened further to denote small projecting pieces or decorative fastenings.