From hard +‎ court.

hardcourt (plural hardcourts)

1. A tennis court having a hard surface, frequently concrete
   • 2009 January 18, Christopher Clarey, “Top-Ranked Men and Women Focused on Australian Open Title”, in New York Times:

     To sum up, it is not at all unreasonable for the British to expect great things from Murray this season, particularly on the hardcourts he prefers.

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