Unity (noun)

1. The state of being united or joined as a whole.
2. The state of being joined together as a single entity.
3. The state of being in agreement or of having a common goal.

Origin:

Middle english: from old french uniti, from latin unitas, from unum "one".

Examples:

1. The unity of the country.
2. The unity of the family.
3. The unity of the team.