What is "jugerum"

n. a Roman unit of measurement of area, equivalent to 0.65 acres

, , or (in Latin, the last form, as a neuter noun of the third declension, is very common in the oblique cases and in the plural) was a Roman unit of measurement of area, 240 pedes (Roman feet) or 71.0 m in length and 120 pedes or 35.5 m in breadth, containing therefore 28,800 pedes quadratum. That is 0.623 acre or 0.25 ha.

It was the double of the , and from this circumstance, according to some writers, it derived its name. It seems probable that, as the word was evidently originally the same as , a yoke, and as , in its original use, meant a path wide enough to drive a single beast along, that originally meant a path wide enough for a yoke of oxen, namely, the double of the in width; and that when was used for a square measure of surface, the , by a natural analogy, became the double of the ; and that this new meaning of it superseded its old use as the double of the single .

Pliny the Elder states:

"That portion of land used to be known as a ‘jugerum,’ which was capable of being ploughed by a single ‘jugum,’ or yoke of oxen, in one day; an ‘actus’ being as much as the oxen could plough at a single spell, fairly estimated, without stopping. This last was one hundred and twenty feet in length; and two in length made a jugerum."

The uncial division as was applied to the , its smallest part being the of 100 sq ft or 9.2 m². Thus, the contained 288 (Varro, R. R. l.c.). The was the common measure of land among the Romans. Two formed an , a hundred heredia a centuria, and four a . These divisions were derived from the original assignment of landed property, in which two were given to each citizen as heritable property.

Columella states:

"The square actus is bounded by 120 feet each way: when doubled it forms a iugerum, and it has derived the name iugerum from the fact that it was formed by joining."