Aperture is the amount of light that is let through the lens to the sensor. All lenses have an aperture. An aperture is a small device within the lens that controls the amount of light admitted through an opening. In photography, aperture is the way of measuring the size of the opening in the lens that can be adjusted to control the amount of light that reaches the sensor. In photography, size of the aperture is measured in F-stop; and in film, the size of the aperture is measured in T-stop.
So looking at the table below for a focal length of 24mm and an aperture of f8 we see the hyperfocal distance is 2.88m. That means if we focus at a distance of 2.88m, the depth of field will extend from 1.44m to infinity.