masticinChem.|ˈmæstɪsɪn| Also -ine. [f. mastic + -in.] The substance which remains undissolved after dissolving mastic in alcohol. 1844in Hoblyn Dict.Med.1883Encycl.Brit. XV 621/2 The insoluble portion [of Mastic], Beta resin or Masticin..is a translucent colourless tough substance.