the action of opening and closing something (often used with 'suru'); refers to opening/closing doors, windows, etc.
換気のために窓の開け閉めをこまめにしてください。
Please open and close the windows often to ventilate.
赤ちゃんがいるから玄関の開け閉めは静かにしてね。
There’s a baby here, so please open and close the front door quietly.
ドアの開け閉めが激しいと床に音が響く。
If the door is opened and closed forcefully, the noise echoes on the floor.