foursome (n.)

• biquadrate
• bout
• contest
• decathlon
• doubles
• event
• four
• game
• go
• match
• meet
• pentathlon
• play
• quad
• quadrangle
• quadrature
• quadrennium
• quadrilateral
• quadrille
• quadruplet
• quartet
• quatern
• quaternary
• quaternion
• quaternity
• race
• rectangle
• runoff
• singles
• sport
• square
• tetrad
• tetragon
• tetragram
• tetragrammaton
• tetrahedron
• tetralogy
• threesome
• twosome