Lewis & Short

1. ō̆crĕa, ae, f. [ὄκρις, a prominence], x greave or leggin (made of mixed metal, and used to protect the legs of foot-soldiers, and also of hunters and country people; it was sometimes worn only on one leg): ocrea, quod opponebatur ob crus, Varr. L. L. 5, § 118 Müll.: ocrem montem confragosum dicebant antiqui. Hinc ocreae dictae inaequaliter tuberatae, Paul. ex Fest. p. 180 Müll.: ocreas et cristas invenere Cares, Plin. 7, 56, 57, § 200: leves, Verg. A. 7, 634.
The Samnites wore a greave only on the left leg: sinistrum crus ocreā tectum, Liv. 9, 4 (cf. Sil. 8, 419).
Worn by heavy-armed Romans on the right leg, Veg. Mil. 1, 20.
Worn by hunters; v. ocreatus.
By rustics, Verg. M. 121: ocreas vendente puellā, i. e. parting with the attire of a gladiator, Juv. 6, 258.