trag·a·canth 
(tr
ăg
ə-k
ănth
′, tr
ăj
-)
n. 1. Any of several spiny Asian shrubs of the genus Astragalus of the pea family, especially A. gummifer, of the Middle East, yielding a gum used in pharmaceuticals, adhesives, and textile printing, and as an emulsifier and thickener in foods.
2. The gum of any of these plants.
[Latin tragacantha, from Greek tragakantha : tragos, goat (probably from the resemblance of the drops of hardened gum to tiny goat horns in shape, color, and texture when they are collected off the plant); see TRAGIC + akantha, thorn, spine.]