1. Biology Living or able to live both on land and in water.
2. Able to operate both on land and in water: amphibious tanks.
3. Relating to or organized for a military landing by means of combined naval and land forces.
4. Of a mixed or twofold nature.
[From Latin amphibius, from Greek amphibios; see AMPHIBIAN.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.