trisaccharide: any of a variety of carbohydrates that yield three monosaccharide molecules on complete hydrolysis
molecule: (physics and chemistry) the simplest structural unit of an element or compound
pinopsida: most conifers: in some systems classified as a class (Pinopsida) and in others as a subdivision (Pinophytina); used in some classifications for one of five subdivisions of Gymnospermophyta