1. Any of various small, wingless, bloodsucking insects of the order Siphonaptera that are parasitic on mammals and birds and can jump long distances.
2. Any of various small crustaceans that resemble or move like fleas, such as the water flea.
a flea in (one's) ear
An annoying hint or a stinging rebuke.
[Middle English fle, from Old English flēah.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.