The Collaborative International Dictionary of English v.0.48:
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. [Webster 1913 Suppl.]WordNet (r) 3.0 (2006):
hollandaise n 1: eggs and butter with lemon juice