| genus melilotus | (n) Old World herbs: the sweet clovers |
| melampodium | (n) herbs and subshrubs of warm North America, Syn. genus Melampodium |
| melampsora | (n) rusts having sessile one-celled teliospores in a single layer, Syn. genus Melampsora |
| melanerpes | (n) a genus of Picidae, Syn. genus Melanerpes |
| melanitta | (n) scoters, Syn. genus Melanitta |
| melanogrammus | (n) haddock, Syn. genus Melanogrammus |
| melanoplus | (n) New World migratory locusts and common American grasshoppers, Syn. genus Melanoplus |
| melanotis | (n) a genus of Mimidae, Syn. genus Melanotis |
| melastoma | (n) type genus of Melastomataceae; Asiatic shrubs with leathery leaves and large purple flowers followed by edible fleshy black berries, Syn. genus Melastoma |
| meleagris | (n) type genus of the Meleagrididae: wild and domestic turkeys, Syn. genus Meleagris |
| meles | (n) in some classifications: type genus of the subfamily Melinae, Syn. genus Meles |
| melia | (n) type genus of the Meliaceae: East Indian and Australian deciduous trees with leaves resembling those of the ash, Syn. genus Melia |
| melicoccus | (n) tropical American trees and shrubs bearing berries, Syn. genus Melicocca, Melicocca, genus Melicoccus |
| melicytus | (n) a genus of deciduous shrubs or trees; fruit is a berry; grow in New Zealand and Fiji and Solomon Islands, Syn. genus Melicytus |
| melissa | (n) a genus of Old World mints of the family Labiatae, Syn. genus Melissa |
| mellivora | (n) ratels, Syn. genus Mellivora |
| melocactus | (n) genus of strongly ribbed globose or spheroid cacti of tropical South and Central America and the Caribbean, Syn. genus Melocactus |
| melogale | (n) a genus of Mustelidae, Syn. genus Melogale |
| melolontha | (n) a genus of Melolonthidae, Syn. genus Melolontha |
| melophagus | (n) an arthropod genus of wingless flies including the sheep ked, Syn. genus Melophagus |
| melopsittacus | (n) a genus of Psittacidae, Syn. genus Melopsittacus |
| melospiza | (n) American song sparrow and swamp sparrow, Syn. genus Melospiza |
| melursus | (n) sloth bears; in some classifications not a separate genus from Ursus, Syn. genus Melursus |