focussing vs immersion

focussing and immersion both are nouns.

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

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

Other hypernyms of focussing include absorption, concentration, engrossment.

focussing (noun)	immersion (noun)
the concentration of attention or energy on something	a form of baptism in which part or all of a person's body is submerged
	the act of wetting something by submerging it
	complete attention; intense mental effort
	sinking until covered completely with water
	(astronomy) the disappearance of a celestial body prior to an eclipse