All 3 Uses

focus
in
The Five People You Meet in Heaven
(Edited)

For a moment, Eddie stared, his mouth slightly open, his eyes bringing the scene into tighter focus.
p. 60.9 *

focus = view (a state where something can be seen clearly)
Eddie tried to focus. The heat was intense, and he shielded his eyes with his free hand. He couldn't be sure, but he thought he'd just seen a small figure running inside the fire.
p. 81.9

focus = adjust vision to see something clearly
He blinks hard against the darkness, trying desperately to focus on his arm, his knuckles, anything to know that he is here, in the apartment over the bakery, and not back in the war, in the village, in the fire.
p. 117.1 *

focus = concentrate

Definitions:

(1) (focus as in: Turn your focus to question #2.)
to direct attention or effort toward a single thing; or the ability to do so without getting distracted
(2) (focus as in: The focus of our study is...)
where attention is concentrated or directed
(3) (focus as in: bring into focus; or out of focus)
a state where something has come into view or can be seen clearly; or an adjustment made to permit a clear view
(4) (focus as with technical usage)
technical usage typically involves some sense of center or concentration such as:
- physics — a point where things come together such as the point where light rays meet
- geometry — a fixed reference point (as of a parabola)
- geology — the point of origin of an earthquake
See a comprehensive dictionary for other less common meanings.
(5) (meaning too rare to warrant focus)