Source : Webster's Revised Unabridged Dictionary (1913)

Angusticlave \An*gus"ti*clave\ ([a^]n*g[u^]s"t[i^]*kl[=a]v), n.
   [L. angustus narrow + clavus a nail, a stripe.] (Rom. Antiq.)
   A narrow stripe of purple worn by the equites on each side of
   the tunic as a sign of rank.