1. Capable of success or continuing effectiveness; practicable: a viable plan; a viable national economy. See Synonyms at possible.
a. Capable of living, developing, or germinating under favorable conditions: viable spores.
b. Capable of living outside the uterus. Used of a fetus or newborn.
[French, from vie, life, from Old French, from Latin vīta; see gwei- in the Appendix of Indo-European roots.]
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.