n. pl. pi·ra·cies
a. Robbery or other serious acts of violence committed at sea.
b. The hijacking of an airplane: air piracy.
2. Copyright or patent infringement: software piracy.
3. The illegal interception or use of radio or television signals.
4. An instance of piracy: a surge of piracies.
[Medieval Latin pīrātia, from Late Greek peirāteia, from Greek peirātēs, pirate; see PIRATE.]
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.