The Collaborative International Dictionary of English v.0.48:
Algin \Al"gin\, n. (Chem.) A nitrogenous substance resembling gelatin, obtained from certain alg[ae]. [Webster 1913 Suppl.]WordNet (r) 3.0 (2006):
algin n 1: a gum used especially as a thickener or emulsifier [syn: algin, alginic acid]