Meaning : An undivided or unbroken completeness or totality with nothing wanting.

Example : The integrity of the nervous system is required for normal development.
He took measures to insure the territorial unity of Croatia.

Synonyms : integrity, wholeness

Meaning : The smallest whole number or a numeral representing this number.

Example : He has the one but will need a two and three to go with it.
They had lunch at one.

Synonyms : 1, I, ace, one, single

Meaning : The quality of being united into one.

Synonyms : oneness