The noun unity has 3 senses (first 3 from tagged texts)
1. (19) integrity, unity, wholeness -- (an undivided or unbroken completeness or totality with nothing wanting; "the integrity of the nervous system is required for normal development"; "he took measures to insure the territorial unity of Croatia")
2. (3) one, 1, I, ace, single, unity -- (the smallest whole number or a numeral representing this number; "he has the one but will need a two and three to go with it"; "they had lunch at one")
3. (2) oneness, unity -- (the quality of being united into one)