pistou

1. A sauce made of garlic, basil, olive oil, and often Parmesan, used on pasta or in soups and stews.
2. A soup or stew flavored with this sauce.

[French, from Provençal, from pestar, to crush, from Old Provençal, from Late Latin pistāre. See piston.]

[pees-TOO] A mixture of crushed basil, garlic and olive oil used as a condiment or sauce. It's the French version of Italy's pesto. See also soupe au pistou.