What is "pasilla"

n. A variety of chili (a dried chilaca), used especially in sauces.

The pasilla chile or chile negro is the dried form of the chilaca chili pepper, a long and narrow member of species Capsicum annuum. Named for its dark, wrinkled skin and pronounced pah-SEE-yah (literally "little raisin"), it is a mild to medium-hot, rich-flavored chile. As dried, it is generally 6 to 8 in (15 to 20 cm) long and 1.0 to 1.5 in (2.5 to 4 cm) in diameter.

The fresh narrow chilaca can measure up to 9.0 in (22 cm) long and often has a twisted shape, which is seldom apparent after drying. It turns from dark green to dark brown when fully mature.

In the United States, producers and grocers often incorrectly use 'pasilla' to describe the poblano, a different, wider variety of pepper, the dried form of which is called an ancho.