"prickly seed vessel of some plants," c. 1300, burre, from a Scandinavian source (compare Danish borre, Swedish hard-borre, Old Norse burst "bristle"), from PIE *bhars- (see bristle (n.)). Transferred 1610s to "rough edge on metal," which might be the source of the sense "rough sound of the letter -r-" (see burr). Also the name given to various tools and appliances.
)window.location='https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=byronic106@yahoo.com&lc=US&item_name=Donation+to +Help+Keep+Etymonline+Free+and+Open&no_note=0&cn=&curency_code=USD&bn=PP-DonationsBF:btn_donateCC_LG.gif:NonHosted'){kind=link}