The Collaborative International Dictionary
chuckstone
Chuck \Chuck\ (ch[u^]k), n.
A small pebble; -- called also chuckstone and chuckiestone. [Scot.]
pl. A game played with chucks, in which one or more are tossed up and caught; jackstones. [Scot.]
Wiktionary
chuckstone
n. (context Scotland English) A chuck; a pebble.