That bit about it being common in mexican cooking could be a hint why us Texoids call the stuff cilantro.

Pico de Gallo:
Coarsely chop tomatoes, cilantro, jalapeno peppers and onion. Stir, and squeeze lemon juice over the mixture. Serve as a garnish for dang near anything. Yum!

Yes, it's a sort of relish the name of which translates to 'rooster beak.'