1historical In ancient Rome: a measure of capacity for liquids, equal to one-sixth of a congius. In the Middle Ages: a large measure for liquid, varying locally between 4 and 6 imperial gallons (18 and 27 litres).
2historical In ancient Rome: a measure of capacity for dry substances, equal to one-sixteenth of a modius. In the Middle Ages: a similar measure of varying capacity, often equated to 2 pounds (or approx. 1 kg).
3historical, rare Any one of the six divisions of the city of Venice.
Late Middle English; earliest use found in The Wycliffite Bible (early version). From classical Latin sextārius sextarius; compare -ary.