Dictionary: clingstone   (klĭng'stōn')

Of or relating to a fruit, especially a peach, having flesh that adheres closely to the stone.

A clingstone fruit, especially a peach.

A term used to describe fruit that has a pit to which the flesh clings tenaciously, one of the most well known being the cling or clingstone peach. See also freestone.

The noun has one meaning:

Meaning #1: fruit (especially peach) whose flesh adheres strongly to the pit
  Synonym: cling