Source : Webster's Revised Unabridged Dictionary (1913)

Solstitial \Sol*sti"tial\, a. [L. solstitialis: cf. F.
   solsticial.]
   1. Of or pertaining to a solstice.

   2. Happening at a solstice; esp. (with reference to the
      northern hemisphere), happening at the summer solstice, or
      midsummer. ``Solstitial summer's heat.'' --Milton.