Wiktionary
guar gum
n. a heteropolysaccharide gum, extracted from the guar bean, that is used as a food additive
WordNet
guar gum
n. from seeds of the guar plant; used to thicken foods and as sizing for paper and cloth
Wikipedia
Guar gum
Guar gum, also called guaran, is a galactomannan. It is primarily the ground endosperm of guar beans. The guar seeds are dehusked, milled and screened to obtain the guar gum. It is typically produced as a free-flowing, off-white powder.