Source : Webster's Revised Unabridged Dictionary (1913)

Epistyle \Ep"i*style\, n. [L. epistylium, Gr. ?; 'epi` upon + ?
   column: cf. F. ['e]pistyle.] (Anc. Arch.)
   A massive piece of stone or wood laid immediately on the
   abacus of the capital of a column or pillar; -- now called
   architrave.