The length from front to back; the depth of a room, box, or the sense of depth in a picture or space.
この棚は奥行きが三十センチあります。
This shelf has a depth of 30 centimeters.
部屋に奥行きを出すために鏡を置いた。
I placed a mirror to create a sense of depth in the room.
テーブルの奥行きが浅くて大きなお皿は置けない。
The table is shallow in depth, so large plates can't be placed on it.