engrossment vs concentration

engrossment and concentration both are nouns.

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

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

Other hypernyms of engrossment include assiduity, assiduousness.

As nouns, engrossment and concentration are synonyms defined as:

engrossment and concentration: complete attention; intense mental effort

Other synonyms of engrossment include absorption, immersion.

engrossment (noun)	concentration (noun)
the quality of being intent and concentrated	strengthening the concentration (as of a solute in a mixture) by removing diluting material
the mental state of being preoccupied by something	bringing together military forces
complete attention; intense mental effort	great and constant diligence and attention
	the strength of a solution; number of molecules of a substance in a given volume
	the spatial property of being crowded together
	complete attention; intense mental effort
	increase in density