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