onion fly

noun

1

: a dipterous insect of the family Anthomyiidae whose larva feeds on onion bulbs

especially : an originally European insect (Hylemya antiqua) now widely distributed in America

2

: an insect (Tritoxa flexa) of the family Otitidae with habits like those of the onion fly

called also black onion fly

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

• More than 250,000 words that aren't in our free dictionary
• Expanded definitions, etymologies, and usage notes
• Advanced search features
• Ad free!