What Is The Definition Of Pesto?

The world's most trusted dictionaries agree that pesto is an Italian sauce made from basil, pine nuts, cheese, garlic, and olive oil, usually served with pasta.

What is pesto, exactly?

While precise wording differs, look for a pesto definition in the world's most popular dictionaries, and you'll find a broad agreement. Here's what three of them say:

Oxford English Dictionary
"A sauce of crushed herbs (usually fresh basil leaves), nuts (usually pine nuts), cheese, garlic, and olive oil, typically served with pasta."

Collins Dictionary
"An Italian sauce made from basil, garlic, pine nuts, cheese, and olive oil."

Merriam Webster
"A sauce made especially of fresh basil, garlic, oil, pine nuts, and grated cheese."

There is an alternative way to define pesto, though. The word (pronounced peh·stow) comes from the past participle of the Genoese verb pestâ (Italian: pestare), meaning "to pound" or "to crush." That is a reference to the pestle and mortar that cooks used to make the sauce long before the invention of food processors.

We like that the word "pesto" is based on a verb rather than a noun because that means we can define pesto not just by its ingredients but also by the process required to make it. While it infuriates some traditionalists, we think this gives chefs as much poetic licence as they like to call their sauce a "pesto," even if their recipe contains different ingredients from traditional basil pesto.