The Collaborative International Dictionary of English v.0.48:

Stearoptene \Ste`a*rop"tene\ (-r[o^]p"t[=e]n), n. [Stearic +
   -optene as in elaeoptene.] (Chem.)
   The more solid ingredient of certain volatile oils; --
   contrasted with elaeoptene.
   [1913 Webster]