hărēnātus — Lewis & Short
hărēnātus (aren-), a, um, adj.id.,
I sanded, covered or mixed with sand (very rare):
calx,Cato, R. R. 18, 7; Inscr. Grut. 207.—As subst.: hărēnātum, i (sc. opus), n., sand-mortar, Vitr. 7, 4; Plin. 36, 23, 55, § 176 sq.