Source : Webster's Revised Unabridged Dictionary (1913)

Holarctic \Hol"arc*tic\, a. [Holo- + arctic.]
   Of or pert. to the arctic regions collectively; specif.
   (Zo["o]geography), designating a realm or region including
   the northern parts of the Old and the New World. It comprises
   the Palearctic and Nearctic regions or subregions.