conviviality

Concise Oxford English Dictionary © 2008 Oxford University Press:
convivial /kənˈvɪvɪəl/

▶adjective (of an atmosphere or event) friendly, lively, and enjoyable.

■ cheerful and sociable.

– derivatives
conviviality noun,
convivially adverb.

– origin C17 (in the sense ‘fit for a feast’): from L. convivialis, from convivium ‘a feast’.