Sin`is*tror"sal (?), a. [L. sinistrorsus, sinistroversus, turned toward the left side; sinister left + vertere, vortere, versum, vorsum, to turn.] Rising spirally from right to left (of the spectator); sinistrorse.

Sin`is*tror"sal (?), a. [L. sinistrorsus, sinistroversus, turned toward the left side; sinister left + vertere, vortere, versum, vorsum, to turn.] Rising spirally from right to left (of the spectator); sinistrorse.