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uncia [Latin]

(Plural, unciae.) Literally, “a twelfth part.” The word is the source of the English words “ounce” and “inch,” as well as the names of many units in other languages.

1

An ancient Roman unit of length, a twelfth of a pes, about 24.6 millimeters.

2

An ancient Roman unit of weight, a twelfth of a libra, about 27.3 grams.

The Romans had special names for quantities of unciae.

Number of unciae	Symbol	Special name
1/24th of an uncia		scrupulus
1/12th of an uncia		semisextula
1/6th of an uncia		sextula
1/3rd of an uncia		duella
1/4th of an uncia		sicilicus
half an uncia		semiuncia
1	-
2	=	sextans
3	=-	quadrans
4	==	trieme
5	==-	quincunx
6 (half a libra)	S	semis
7	S-	septunx
8	S=	bes
9	S=-	dodrans
10	S==	dextans
11	S==-	deunx

3

An ancient Roman unit of capacity, a twelfth of a hemina, about 5.5 milliliters.

4

A ancient Roman unit of land area = 1/12 jugerum.