senate vs Senate

senate and Senate both are nouns.

Word	Noun	Adjective	Verb	Adverb
senate	Yes	No	No	No
Senate	Yes	No	No	No

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

Other hyponyms of senate include U.S. Senate, United States Senate, US Senate.

senate (noun)	Senate (noun)
assembly possessing high legislative powers	the upper house of the United States Congress