arrowroot

Etymology

arrow +‎ root, from being used on wounds from poison darts to absorb the poison..

Alternatively, from Arawak aru-aru, with arrow + root being a phono-semantic matching.

Noun

arrowroot (countable and uncountable, plural arrowroots)

1. A large perennial herb (Maranta arundinacea - family Marantaceae) native to the Caribbean area. It has large green leaves about 15 centimeters long with white stripes.
2. (uncountable) A starchy substance obtained from the roots of the arrowroot plant used as a thickener.