fos·ter (fôstər, fŏstər)
tr.v. fos·tered, fos·ter·ing, fos·ters
1. To bring up; nurture: bear and foster offspring. See Synonyms at nurture.
2. To promote the growth and development of; cultivate: detect and foster artistic talent. See Synonyms at advance.
3. To nurse; cherish: foster a secret hope.
1. Providing parental care and nurture to children not related through legal or blood ties: foster parents; foster grandparents; a foster home.
2. Receiving parental care and nurture from those not related to one through legal or blood ties: foster children.
[Middle English fostren, from Old English *fōstrian, to nourish, from fōstor, food, nourishing; see pā- in the Appendix of Indo-European roots.]
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.