blackboard
 US /ˈblæk.bɔːrd/
 UK /ˈblæk.bɔːrd/

1. 
黒板
a large board with a smooth, dark surface, typically green or black, used for writing on with chalk, especially in schools
:
• 
The teacher wrote the math problem on the blackboard.
先生は算数の問題を黒板に書いた。
• 
We used to draw pictures on the blackboard during recess.
休憩時間に黒板に絵を描いたものだ。