noun
every corner; every nook and cranny
Used for physical spaces or thoroughness; emphasizes that no part is left out. Often appears with verbs like 探す, 掃除する, or 知る.
部屋の隅々まで掃除した。
I cleaned every corner of the room.
彼はその町の隅々を知っている。
He knows every nook and cranny of the town.
隅 means a single corner or nook; 隅々 is the emphatic reduplicated form meaning every corner.
Reduplication of 隅 (corner) to express 'every corner'.