Wordnet 3.0
NOUN (2)
1. 
 badminton played with one person on each side; 
2. 
 tennis played with one person on each side; 
The Collaborative International Dictionary of English v.0.48:
singles \sin"gles\, n. pl.
   See Single, n., 2.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
singles \sin"gles\, a.
   For unmarried persons, or catering especially to unmarried
   persons; as, a singles bar; a singles party.
   [PJC]
WordNet (r) 3.0 (2006):
singles
    n 1: badminton played with one person on each side
    2: tennis played with one person on each side