Greek λεπτόν. Literally "a thin one". Also called Mite, Lepta, Widow's mite.
The smallest coin in circulation — the widow put in two of them, and was told she had given more than anyone.
Wage
about 6 minutes' work (about 6 minutes' work).
Reckoned from two to the quadrans.
Diameter
1.3–1.5 cm (0.512–0.591 in).
Reckoned from surviving star-and-anchor lepta of Alexander Jannaeus, the coin usually identified as the widow's mite.
A lepton is the smallest coin anybody handled: two of them made a quadrans, which was a quarter of the cheapest copper coin, which was a sixteenth of a day's wage. The whole force of the scene in the treasury is that the sum is negligible by every measure except the one being applied — she gave two, and could have kept one.
Sizes are the range of surviving examples, and coins of one name varied from mint to mint. Bronze paid for small things and silver for wages and taxes: the widow gave two lepta (Mark 12:42), the temple tax was a didrachma (Matthew 17:24), and a stater paid it for two (17:27).