Thoroughly; everywhere from one corner to another; covering every part (used for looking through, cleaning, reading, etc.).
引っ越しの前に部屋を隅から隅まで掃除した。
Before moving, I cleaned the room from top to bottom.
彼はその本を隅から隅まで読んで、メモを取った。
He read the book cover to cover and took notes.
観光客は町を隅から隅まで歩き回った。
The tourists walked all around the town, exploring every corner.