Easton's Bible Dictionary
(1.) Matthew 10:29; Luke 12:6. Greek assarion, i.e., a small as, which was a Roman coin equal to a tenth of a denarius or drachma, nearly equal to a halfpenny of our money.
(2.) Matthew 5:26; Mark 12:42 (Gr. kodrantes), the quadrant, the fourth of an as, equal to two lepta, mites. The lepton (mite) was the very smallest copper coin.
Noah Webster's New International Dictionary of the English Language
1. (n.) The fourth of a penny; a small copper coin of Great Britain, being a cent in United States currency.
2. (n.) A very small quantity or value.
3. (n.) A division of land.