A hard medicated paste made of lard or oil mixed with wax or resin WordNet 3.0 & Open English WordNet

Cerate, historically simple cerate, is an unctuous preparation for external application, of a consistency intermediate between that of an ointment and a plaster. Wikipedia

An unctuous preparation for external application — mainly wax (or resin or spermaceti) mixed with oil, lard, and various medicinal ingredients — of a consistency between ointment and plaster, so that it can be spread upon cloth without the use of heat, but does not melt when applied to the skin. Wiktionary