(N. Amer. informal)a persistent source of irritation(北美，非正式)恼人的事，令人烦恼的事
柯林斯高阶英汉双解学习词典释义
N-COUNT
（某些植物）带芒刺的小果实
A burr is the part of some plants which contains seeds and which has little hooks on the outside so that it sticks to clothes or fur.
N-COUNT
（英语方言中的）颤动小舌的r音，粗喉音
If someone has a burr, they speak English with a regional accent in which 'r' sounds are pronounced more strongly than in the standard British way of speaking.