1A board used in classrooms (or similar places) that you write on with chalk and can erase — a blackboard/chalkboard.
教室の黒板に今日の予定が書いてある。
The schedule for today is written on the classroom blackboard.
先生はチョークで黒板に線を引いた。
The teacher drew a line on the blackboard with chalk.
黒板を消すので、写真を撮っておいてください。
I'm going to erase the blackboard, so please take a photo first.