Quenya
sar
(small) stone
* sardincë
noun. pebble
Sindarin
sarn
noun/adjective. (small) stone, pebble, stony (place), **with many stones, *[N.] stone as a material
Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
Early Quenya
hyelle
noun. pebble
tolot
noun. pebble, cobble-stone
* lalle
noun. pebble
sar (sard-, as in pl. sardi) noun "(small) stone" (SAR). In Elessar, q.v. Since Tolkien let this name have a stem in -sarn- (genitive Ele[s]sarno, VT49:28), he may seem to have changed the stem-form of sar from sard- to sarn-.