Lord's Day vs Dominicus

Lord's Day and Dominicus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Lord's Day	Yes	No	No	No
Dominicus	Yes	No	No	No

As nouns, Lord's Day and Dominicus are synonyms defined as:

Lord's Day and Dominicus: first day of the week; observed as a day of rest and worship by most Christians

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

Lord's Day (noun)	Dominicus (noun)
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