Entry 3 senses · 2 variants Webster, 1913 Separatory · Sep·a·ra·to·ry · IPA a. n. 01 a. Separative. 1. Separative. 02 n. An apparatus used in separating, as a separating funnel. 1. An apparatus used in separating, as a separating funnel.(Chem.) 2. A surgical instrument for separating the pericranium from the cranium.(Surg.) [Obs.]