What is an aperture on a camera and how does it affect the quality of the photographs taken?

An aperture on a camera is the opening through which light enters the camera lens. It affects the quality of photographs by controlling the amount of light that reaches the camera sensor, as well as the depth of field in the image. A larger aperture lets in more light and creates a shallower depth of field, resulting in a blurred background and a sharper subject. A smaller aperture lets in less light and creates a deeper depth of field, keeping more of the image in focus.