Party (noun)

1. A social gathering for entertainment and fun.
2. A political group or organization.
3. A legal agreement between two or more parties.

Origin:

Mid 17th century: from french parti, from latin partitus, past participle of partiri 'to divide'. the original sense was "a division, a part".

Examples:

1. The birthday party was a lot of fun.
2. She is a member of the Democratic Party.
3. The contract was signed by all parties involved in the agreement.