atlas vs dialect atlas

atlas and dialect atlas both are nouns.

Word	Noun	Adjective	Verb	Adverb
atlas	Yes	No	No	No
dialect atlas	Yes	No	No	No

As nouns, dialect atlas is a hyponym of atlas; that is, dialect atlas is a word with a more specific, narrower meaning than atlas:

atlas: a collection of maps in book form
dialect atlas: an atlas showing the distribution of distinctive linguistic features

Other hyponyms of atlas include linguistic atlas, star atlas.

atlas (noun)	dialect atlas (noun)
a figure of a man used as a supporting column	an atlas showing the distribution of distinctive linguistic features
the 1st cervical vertebra
a collection of maps in book form