Aperture: Refers to the opening of a lens’s diaphragm through which light passes. It is calibrated in f/stops and it generally written as numbers such as 1.2, 2,8, 4, 5.6, 8, 11.

Depth of Field: The distance between the closest and farthest objects in a photo that appears acceptably sharp. Now your camera can only focus sharply at one point. But the transition from sharp to unsharp is gradual.
The depth of field can be calculated based on focal length, distance to subject, the acceptable circle of confusion size, and aperture.