In general use, herbs are any plants used for flavoring, food, medicine, or perfume. Culinary use typically distinguishes herbs as referring to the leafy green parts of a plant (either fresh or dried), from a "spice", a product from another part of the plant (usually dried), including seeds, berries, bark, roots and fruits.
In American botanical English the term "herb" is also used as an abbreviation of "herbaceous plant". This usage is rarely found in British English.
Herbs have a variety of uses including culinary, medicinal, and in some cases spiritual usage. General usage of the term "herb" differs between culinary herbs and medicinal herbs. In medicinal or spiritual use any of the parts of the plant might be considered "herbs", including leaves, roots, flowers, seeds, resin, root bark, inner bark (and cambium), berries and sometimes the pericarp or other portions of the plant.
The word "herb" is pronounced /ˈɜrb/ by many U.S. speakers, or /ˈhɜrb/ by other U.S. speakers and all other English speakers.