knowledge domain vs knowledge base

knowledge domain and knowledge base both are nouns.

Word	Noun	Adjective	Verb	Adverb
knowledge domain	Yes	No	No	No
knowledge base	Yes	No	No	No

As nouns, knowledge domain and knowledge base are synonyms defined as:

knowledge domain and knowledge base: the content of a particular field of knowledge

Other synonyms of knowledge domain include domain.

knowledge domain (noun)	knowledge base (noun)
the content of a particular field of knowledge	the content of a particular field of knowledge