From The Collaborative International Dictionary of English v.0.48 [gcide]:
focusing \focusing\, focussing \focussing\n.
1. the concentration of attention or energy on something.
Syn: focus, focussing.
[WordNet 1.5]
2. the act of bringing into focus.
Syn: focalization, focalisation.
[WordNet 1.5]
From WordNet (r) 3.0 (2006) [wn]:
focussing
n 1: the concentration of attention or energy on something; "the
focus of activity shifted to molecular biology"; "he had no
direction in his life" [syn: focus, focusing,
focussing, focal point, direction, centering]