sociability

1. The disposition or quality of being sociable.
2. An instance of being sociable.

noun

The quality of being pleasant and friendly: affability, agreeability, agreeableness, amenity, amiability, amiableness, congeniality, congenialness, cordiality, cordialness, friendliness, geniality, genialness, pleasantness, sociableness, warmth. See attitude/good attitude/bad attitude/neutral attitude, good/bad.

Definition: friendliness
Antonyms: solitariness, uncommunicativeness, unfriendliness, unsociability

Any form of social interaction in which people become involved solely for its own sake. For example, having a drink with a friend in the sports club bar. Although pursued for the sake of the pleasure it gives to the individual, sociability may have a serious underlying purpose, for example, in reinforcing social bonds.

The noun has one meaning:

Meaning #1: the relative tendency or disposition to be sociable or associate with one's fellows
  Synonym: sociableness
  Antonym: unsociability (meaning #1)