Definition of "greenfly"

Any of several kinds of common insects green in color:

1. Certain aphids (Aphidoidea), commonly known as greenfly in Britain and the Commonwealth

   1. especially, Myzus persicae, green peach aphid  examples

2. Lucilia sericata, common green bottle fly  examples

3. Tabanus nigrovittatus, a biting horsefly more commonly known as the greenhead horsefly, greenhead fly, or greenhead  examples

4. Odontomyia chloris (syn. Musca chloris)  examples