field of view
n. pl. fields of view
1. The area that one can observe at a given moment without turning one's head or otherwise moving.
a. The measure of the width of the area rendered into an image by the lens system of an optical instrument. Angular field of view is measured in degrees. Linear field of view is measured as a ratio of lengths, such as feet per thousand feet or millimeters per meter of distance from the lens.
b. The area rendered into such an image.
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.