focussing vs engrossment

focussing and engrossment both are nouns.

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

As nouns, engrossment is a hypernym of focussing; that is, engrossment is a word with a broader meaning than focussing:

Other hypernyms of focussing include absorption, concentration, immersion.

focussing (noun)	engrossment (noun)
the concentration of attention or energy on something	the quality of being intent and concentrated
	the mental state of being preoccupied by something
	complete attention; intense mental effort