I'SINGLASS, noun i'zinglass. [that is, ise or ice-glass.] A substance consisting chiefly of gelatin, of a firm texture and whitish color, prepared from the sounds or air-bladders of certain fresh water fishes, particularly of the huso, a fish of the sturgeon kind, found in the rivers of Russia. It is used as an agglutinant and in fining wines.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI