noun

1. Obsolete a third
2. terce
3. an old unit of liquid measure, equal to pipe (42 gallons)
4. a cask of this capacity, between a barrel and a hogshead in size
5. Fencing the third defensive position, from which a lunge or parry can be made

Etymology: ME terce < OFr < L tertia, fem. of tertius, (a) third < base of tres, three