to insert; to put in; to thrust in; to plug in
to come in (of light); to shine in; to stream in; to pour in
to have a griping pain (in the stomach, chest, etc.)
コンセントにプラグを差し込んだ。
I plugged in the plug to the outlet.
鍵を差し込んでドアを開けた。
I inserted the key and opened the door.
鍵を差し込んでいるのに、ドアが開かない。
The key is inserted, but the door won't open.