Coriander, Coriandrum sativum, is one of the few plants that produce both an herb and a spice; with the others being dill (dill weed and dill seed) and fenugreek (fenugreek leaves and fenugreek seed). From the leaves of the coriander plant comes the herb best known as cilantro or Chinese parsley, while the dry fruits of the plant are recognized as coriander seeds. An individual coriander plant can only be cultivated for one of these, as the “cilantro” leaves must be picked before the plant matures to produce the seeds.
The word coriander is derived from the Greek word “koris”, which means bug and this probably stems from the offensive “buggy” smell that the seed has when unripe. When a recipe calls for coriander, it is almost always referring to the seeds as a spice, and not the leaves of the plant.