The Greek aleuron refers to ground wheat flour or meal, used for baking bread. It appears in the parable of the leaven in Matthew 13:33 and Luke 13:21.
In the parable of the leaven, a woman hides a small amount of yeast in "three measures of flour" until the whole batch rises (Matthew 13:33). The parable describes the kingdom of God's pervasive, transforming power — hidden and seemingly small, yet able to leaven the whole of human society. The use of aleuron (fine flour) also recalls the daily provision God gives: every meal made from flour is a reminder of "give us this day our daily bread" — God's sustaining grace in the ordinary.