The Collaborative International Dictionary of English v.0.48:

Spike \Spike\, n. [Cf. G. spieke, L. spica an ear of grain. See
   Spikenard.] (Bot.)
   Spike lavender. See Lavender.
   [1913 Webster]

   Oil of spike (Chem.), a colorless or yellowish aromatic oil
      extracted from the European broad-leaved lavender, or
      aspic (Lavendula Spica), used in artist's varnish and in
      veterinary medicine. It is often adulterated with oil of
      turpentine, which it much resembles.
      [1913 Webster]