realm vs domain

realm and domain both are nouns.

Word	Noun	Adjective	Verb	Adverb
realm	Yes	No	No	No
domain	Yes	No	No	No

As nouns, domain is a hypernym of realm; that is, domain is a word with a broader meaning than realm:

realm: a knowledge domain that you are interested in or are communicating about
domain: the content of a particular field of knowledge

Other hypernyms of realm include knowledge base, knowledge domain.

As nouns, domain is a hypernym of realm; that is, domain is a word with a broader meaning than realm:

Other hypernyms of realm include demesne, land.

As nouns, domain is a hypernym of realm; that is, domain is a word with a broader meaning than realm:

Other hypernyms of realm include area, arena, field, orbit, sphere.

realm (noun)	domain (noun)
a knowledge domain that you are interested in or are communicating about	the content of a particular field of knowledge
the domain ruled by a king or queen	people in general; especially a distinctive group of people with some shared interest
a domain in which something is dominant	(mathematics) the set of values of the independent variable for which a function is defined
	territory over which rule or control is exercised
	a particular environment or walk of life