Both Uses of

focus
in
Holes, by Louis Sachar

After focusing on Big Thumb for so long, it was as if the rock had absorbed his energy and now acted like a kind of giant magnet pulling him toward it.
p. 170.8 *

focusing = concentrating

His mind was focused on the tiny claws that moved up and down his skin and through his hair.
p. 208.9

Definitions:

(1) (focus as in: Turn your focus to question #2.)
verb: to concentrate, look at, or pay attention to

noun: the act of concentration, or the ability to concentrate

(to concentrate is to direct attention or effort towards a single thing)
(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.