Hello...This question was in one of the liquid smoke letters and
I never saw an answer, so I will give my response.
Coriander is the seed, and cilantro is the leaf, either dried or
fresh. I have the dried cilantro, and the coriander seed. I use
the coriander in my Indian-style recipes and the cilantro in the
Mexican-style recipes. I read they are not interchangeable
and I have never tried. They do smell different.