Extended Strong's Greek Lexicon (Abbott-Smith based)
stone
Usage: ψῆφος, -ου, ἡ (ψάω, to rub) [in LXX: Exo.4:25 (צֹר), La 3:16 (חָצָץ), Ecc.7:26 (25) (צֹר), 4Ki.12:4 (5) A, Sir.18:10, 4Ma.15:26 * ;] __1. a small smooth stone, a pebble: ψ. λευκή (for suggestions as to the meaning, see Swete, in l), Rev.2:17. __2. From the use of pebbles in voting, a vote: Act.26:10.† (AS)