'bur' originates from Old English 'bur' or 'byr', ultimately from Proto-Germanic '*buraz', where the root meant 'seed vessel' or 'shell containing seeds'.

'bur' changed from Old English 'bur' (and Middle English forms such as 'burre') and later coexisted with the variant spelling 'burr', eventually resulting in the modern English forms 'bur' and 'burr'.

Initially, it meant 'a seed vessel with hooked bracts'; over time the sense extended metaphorically to 'a rough edge left by cutting' and to the name of the small rotary cutting tool used to remove or create such edges.