Source : Webster's Revised Unabridged Dictionary (1913)

   {Vernal equinox} (Astron.), the time when the sun crosses the
      equator when proceeding northward.

   {Vernal grass} (Bot.), a low, soft grass ({Anthoxanthum
      odoratum}), producing in the spring narrow spikelike
      panicles, and noted for the delicious fragrance which it
      gives to new-mown hay; -- also called {sweet vernal
      grass}. See Illust. in Appendix.

   {Vernal signs} (Astron.), the signs, Aries, Taurus, and
      Gemini, in which the sun appears between the vernal
      equinox and summer solstice.

Source : WordNet®

vernal equinox
     n 1: March 21 [syn: {March equinox}, {spring equinox}] [ant: {autumnal
          equinox}]
     2: (astronomy) the equinoctial point that lies in the
        constellation of Pisces