1 = bur.

/bɜ:(r); bɝ/
n (usu sing 通常作单数)
1 whirring or humming sound made eg by parts of a machine turning quickly or by a telephone 隆隆声（如机器部件快速运转时发出的）; 嗡嗡声（如电话机的声音）.
2 strong pronunciation of the `r' sound, typical of certain English accents; accent using this 浓重的r音（为英语某些方音）; 带有浓重的r音的口音
*speak with a soft West Country burr 用柔和的英国西南部地区的腔调说话.

v [I] make a burr 发浓重的r音.

n[C]
[Sense: 1,4; Date: 1600-1700; Origin: Probably from a Scandinavian language]
[Sense: 2-3; Date: 1700-1800; Origin: Probably from the sound.]
alsobur
the seed container of some plants, covered with sharp points that make it stick to things
BrE a way of pronouncing English with a strong 'r' sound
a fairly quiet regular sound like something turning quickly
= whirr
　the burr of a motor
a rough spot on a piece of metal