birch    
noun uk/bɜːtʃ/ us/bɝːtʃ/
  (TREE)     
  [ C ]桦树,白桦树 
a tree with smooth, often white bark (= outer covering) and thin branches
   (PUNISHMENT)    
the birch[ S ] UK 鞭笞;用桦木条抽打
an official punishment in the past, that involved hitting a person across the bottom with thin sticks. The thins sticks are also called the birch.
 birch
verb [ T ] UK ukus
 对…施笞刑
to punish someone with the birch