Chipotle are large (around 2 to 4
inches) jalapeno that have been
dried and
smoked and so are called a "chile ahumado". About 1/5th of the jalapeno crop in
Mexico are made into chipotles. There is also a "chipotle grande" which has been made from huachinango chiles. While available in dried and powdered forms, chipotle are commonly available tinned in a red
adobo sauce.
Chipotle are wonderful in soups, salsas and sauces. The flavours are reminiscent of chocolate and Brazil nuts. On the Scofield scale of heat, chipotle are usually 5-6 out of 10. If you want to know how to make your own adobo sauce, click the hard link. If not, don't.