What is "psephism"

Psephism \Pse"phism\, n. [Gr. ? a decree, fr. ? to vote with a pebble, fr. ? pebble.] (Gr. Antiq.) A proposition adopted by a majority of votes; especially, one adopted by vote of the Athenian people; a statute.
--J. P. Mahaffy.

n. (context historical Ancient Greece English) A proposition adopted by a majority of votes, especially by the vote of the Athenian people; a statute.