Emily Dickinson Lexicon

SE-TA'CEOUS, a. [L. seta, a bristle.]

1. Bristly; set with bristles; consisting of bristles; as, a stiff setaceous tail. – Derham.
2. In botany, bristle-shaped; having the thickness and length of a bristle; as, a setaceous leaf or leaflet. – Martyn. Setaceous worm, a name given to a water worm that resembles a horse hair, vulgarly supposed to be an animated hair. But this is a mistake. – Encyc.