1. One who observes: an observer of local customs; observers of religious holidays.
2. One who is sent to observe and report on events or proceedings without directly participating in them.
a. A crew member on a military aircraft who makes observations.
b. A member of an armed force who watches and reports from an observation post.
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.