Hĕl'i-sphē'rĭc or Hĕl'i-sphē'rĭc-al, a.

a. [For heliospheric, from Gr. ἕλιξ, helix, and σφαιρικός, spherical.] Spiral.

Helispherical line (Math.), the rhomb line in navigation;—so called because, on the globe, it winds round the pole spirally, coming nearer and nearer to it, but never terminating in it. Barlow.