WordWeb Online

1. A close friend, esp. one who often acts as a companion
   - brother, chum [informal], crony [informal], pal [informal], cobber [Austral, informal], bud [N. Amer, informal], compadre, paisano [US]
    
2. An informal and friendly term of address to a stranger
   - mate [informal]

1. Form small teams, especially pairs
   - buddy up [informal]
    
2. Be friendly towards someone; become friends with someone
   - buddy up [informal]

Derived forms: buddies, buddied, buddying

See also: sidekick [informal]

Type of: china [Brit, informal], friend, mate [Brit, informal]

Encyclopedia: Buddy, can you spare a dime