"jackstones" in the noun sense
1. jack, jackstones
game equipment consisting of one of several small six-pointed metal pieces that are picked up while bouncing a ball in the game of jacks
2. jacks, jackstones, knucklebones
a game in which jackstones are thrown and picked up in various groups between bounces of a small rubber ball
Source: WordNet® (An amazing lexical database of English)
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