The Collaborative International Dictionary of English v.0.48:

aioli \aioli\ n. (Cooking)
   a French garlic-flavored mayonnaise. It is often served with
   fish and other seafood, and sometimes with vegetables.

   Syn: aioli sauce, garlic sauce
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

aioli
    n 1: garlic mayonnaise [syn: aioli, aioli sauce, garlic
         sauce]