focussing vs centring

focussing and centring both are nouns.

Word	Noun	Adjective	Verb	Adverb
focussing	Yes	No	No	No
centring	Yes	No	No	No

As nouns, focussing and centring are synonyms defined as:

focussing and centring: the concentration of attention or energy on something

Other synonyms of focussing include centering, direction, focal point, focus, focusing.

focussing (noun)	centring (noun)
the concentration of attention or energy on something	(American football) putting the ball in play by passing it (between the legs) to a back
	the concentration of attention or energy on something