The point where light rays converge through a lens.
The centre of an infection.
Point at which light, sound, or other rays meet, as determined by positions of lenses and other devices; the point of convergence of light after passing through a convex lens is the place at which there is the clearest image.
The point at which rays of light converge after passing through a lens.
The point of convergence of light rays or sound waves.
A focal point in a particular location where diseased plants or lesions from a disease gather and are concentrated. This gathering could be due to a primary source of infection or by chance occurring in an area initially suitable for establishment, ultimately resulting in an altered pattern of transmission for the disease.
The point where beams of light converge after passing through a convex lens.