Quenya 

sar

(small) stone

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-.

* sardincë

noun. pebble
Quenya Group: Neologism. Published by

Sindarin 

sarn

noun/adjective. (small) stone, (small) stone, pebble, pebble, small stone, pebble, stony (place), stony; stony place
Sindarin [RC/163.0306; RC/327.3205; RC/775.0811; SA/sarn.001; UTI/Serni.017; VT42/11.0406; VT42/11.0506] Group: Eldamo. Published by

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!

Qenya 

hyelle

noun. pebble
Qenya [PE16/138.3801; PE16/144.7301] Group: Eldamo. Published by

tolot

noun. pebble, cobble-stone
Qenya [PE15/77.5001; PE15/77.5207] Group: Eldamo. Published by

* lalle

noun. pebble
Qenya [PME/050.6503; QL/050.6401; QL/050.6402] Group: Eldamo. Published by

Gnomish

clocthi

noun. pebble
Gnomish [GL/26.3201] Group: Eldamo. Published by