Source : Webster's Revised Unabridged Dictionary (1913)

Hollandaise sauce \Hol`lan*daise" sauce\, or Hollandaise
\Hol`lan*daise"\, n. [F. hollandaise, fem. of hollandais Dutch.]
   (Cookery)
   A sauce consisting essentially of a seasoned emulsion of
   butter and yolk of eggs with a little lemon juice or vinegar.