What does bur mean?
A bur is a small, rough, prickly structure — most familiarly the barbed seed case of certain plants such as cocklebur and burdock, which clings tenaciously to animal fur, wool, and clothing as an effective means of seed dispersal. The word also denotes a rough, ragged edge or raised lip of material left behind on metal, wood, or plastic by a drill, saw, or file, something machinists routinely remove with deburring tools. By extension, especially in older American usage, a bur can mean a persistent source of annoyance that lodges in the mind much as a bur lodges in a sock. The spelling 'bur' is standard in American English, while British writers usually prefer 'burr', which carries additional meanings including a rolling pronunciation of the letter r. Familiar, concrete, and vivid, the word appears often in descriptions of countryside walks, pets, and workshop practice.
A prickly seed case or flower head that clings to fur and fabric.
"The field was full of burs that hitched rides on our trousers."
A rough edge or ridge of material left on a workpiece by a cutting tool.
"Use a fine file to remove the bur from the drilled hole."
Regular plural; the alternative plural 'burrs' follows the chiefly British spelling.
"After the autumn walk, both dogs were matted with burs."
Velcro was invented after a Swiss engineer examined the burs clinging to his dog's fur under a microscope — nature's fastener became a billion-dollar idea.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bur
Bur dates back to Middle English, appearing in forms such as 'burre', and is likely related to Old Norse 'burra', meaning a dry husk or chaff. It shares its Germanic roots with words like burdock, whose name simply combines 'bur' with 'dock' (a type of weed). The extended sense of a rough edge on worked material developed later, drawing on the image of a jagged, clinging irregularity. The variant spelling 'burr' arose in English orthography and eventually took on extra specialized meanings in British usage.
Related word forms
How bur is actually used
'Bur' is the standard American spelling; British English typically uses 'burr', which additionally carries senses (a trilled r-sound, a regional accent) that 'bur' does not. The word is informal-to-neutral in register and common in rural, gardening, machining, and woodworking contexts.
Easily confused with bur
'Burr' is the chiefly British spelling and also refers to a trilled 'r' sound or a rough edge, while 'bur' is the standard American spelling for the prickly seed case.