arrowroot

Concise Oxford English Dictionary © 2008 Oxford University Press:
arrowroot/ˈarəʊruːt/

▶noun

• 1 a fine-grained starch used in cookery and medicine.

• 2 the herbaceous Caribbean plant from which arrowroot is prepared. [Maranta arundinacea.]

– origin C17: alt. of Arawak aru-aru (lit. ‘meal of meals’) by assoc. with arrow and root1, the plant's tubers being used to absorb poison from arrow wounds.