algin

al·gin

noun \ˈal-jən\

Definition of ALGIN

: any of various colloidal substances derived from marine brown algae and especially giant kelp: as a : alginic acid b : a soluble salt of alginic acid used especially as a stabilizing, emulsifying, or thickening agent in foods (as ice cream), pharmaceuticals, and cosmetics and as a base for dental-impression materials—called also sodium alginate