1 Likewise, at two years of age a cat has reached the same maturity as a person of 25 years, so the second year of a cat's life is equivalent to 10 years (25 minus 15) of a person's. 2  Thereafter, each calendar year a cat ages the equivalent of 4 human years.
countable noun. 1  The focal point of something is the thing that people concentrate on or pay most attention to. 2  the point on the axis of a lens or mirror to which parallel rays of light converge or from which they appear to diverge after refraction or reflection. 3  a central point of attention or interest.
The chief and parallel rays meet at the tip of the image. The third ray, the focal ray, is a mirror image of the parallel ray. The focal ray is drawn from the tip of the object through (or towards) the focal point, reflecting off the mirror parallel to the principal axis.