Quick definitions from WordNet (focus)

▸ noun:  maximum clarity or distinctness of an image rendered by an optical system ("In focus")
▸ noun:  maximum clarity or distinctness of an idea ("The controversy brought clearly into focus an important difference of opinion")
▸ noun:  the concentration of attention or energy on something ("The focus of activity shifted to molecular biology")
▸ noun:  a fixed reference point on the concave side of a conic section
▸ noun:  a point of convergence of light (or other radiation) or a point from which it diverges
▸ noun:  a central point or locus of an infection in an organism ("The focus of infection")
▸ noun:  special emphasis attached to something
▸ verb:  cause to converge on or toward a central point ("Focus the light on this image")
▸ verb:  put (an image) into focus ("Please focus the image")
▸ verb:  become focussed or come into focus ("The light focused")
▸ verb:  direct one's attention on something ("Please focus on your studies and not on your hobbies")
▸ verb:  bring into focus or alignment; to converge or cause to converge; of ideas or emotions

---

▸ Also see focus