Did you mean focus?
focus
noun
°a point at which reflected or refracted rays of light converge.
"The heat of sunlight at the focus of a magnifying glass can easily set dry leaves on fire."
°a point of a conic at which rays reflected from a curve or surface converge.
verb
°To cause (rays of light, etc) to converge at a single point.
°To adjust (a lens, an optical instrument) in order to position an image with respect to the focal plane.