focal infection vs focus

focal infection and focus both are nouns.

Word	Noun	Adjective	Verb	Adverb
focal infection	Yes	No	No	No
focus	Yes	No	Yes	No

focal infection (noun)	focus (noun)
bacterial infection limited to a specific organ or region especially one causing symptoms elsewhere	maximum clarity or distinctness of an image rendered by an optical system
	maximum clarity or distinctness of an idea
	the concentration of attention or energy on something
	a fixed reference point on the concave side of a conic section
	a point of convergence of light (or other radiation) or a point from which it diverges
	a central point or locus of an infection in an organism
	special emphasis attached to something

focal infection (verb)	focus (verb)
	become focussed or come into focus
	put (an image) into focus
	direct one's attention on something
	bring into focus or alignment; to converge or cause to converge; of ideas or emotions
	cause to converge on or toward a central point