The dictionary provides explanations of the meaning and origins of generic and specific names of grasses, one of the largest and economically most important plant families. There are about 12,500 entries, which far exceed in number those of any other dictionary in print. Most of the names published during the past 250 years are included. Throughout the family, the gross morphologies of plants conform to a relatively fixed pattern, thereby restricting the number of descriptive terms available from which to form generic or specific names. Accordingly, many taxa and especially species have names based on usage, locality or collector. Because it is usually easier to remember a technical name once its meaning is known, this work should be of value to a wide audience, including ecologists, agronomists, and anthropologists. Others interested in the history of taxonomy, but not necessarily that of grasses, will find the dictionary a useful resource.