Sun vs Dominicus

Sun and Dominicus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sun	Yes	No	No	No
Dominicus	Yes	No	No	No

As nouns, Sun and Dominicus are synonyms defined as:

Sun and Dominicus: first day of the week; observed as a day of rest and worship by most Christians

Other synonyms of Sun include Lord's Day, Sunday.

Sun (noun)	Dominicus (noun)
the star that is the source of light and heat for the planets in the solar system	first day of the week; observed as a day of rest and worship by most Christians
first day of the week; observed as a day of rest and worship by most Christians