Tapioca \Tap`i*o"ca\, n. [Braz. tapioka: cf. Pg., Sp. & F. tapioca.]

A coarsely granular substance obtained by heating, and thus partly changing, the moistened starch obtained from the roots of the cassava. It is much used in puddings and as a thickening for soups. See Cassava.

Source: Webster's Revised Unabridged Dictionary (1913)