1. Biology An organism that lives and feeds on or in an organism of a different species and causes harm to its host.
a. One who habitually takes advantage of the generosity of others without making any useful return.
b. One who lives off and flatters the rich; a sycophant.
3. A professional dinner guest, especially in ancient Greece.
[Latin parasītus, a person who lives by amusing the rich, from Greek parasītos, person who eats at someone else's table, parasite : para-, beside; see PARA-1 + sītos, grain, food.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 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.