Source : Webster's Revised Unabridged Dictionary (1913)

Interlunar \In`ter*lu"nar\, Interlunary \In`ter*lu"na*ry\, a.
   [Pref. inter- + lunar: cf. L. interlunis.]
   Belonging or pertaining to the time when the moon, at or near
   its conjunction with the sun, is invisible. --Milton.