grand·fa·ther (grăndfä′thər, grăn-)
1. The father of one's mother or father.
2. A forefather; an ancestor.
tr.v. grand·fa·thered, grand·fa·ther·ing, grand·fa·thers
To exempt (someone or something) from a new regulation that prohibits or restricts something: The new ordinance restricts the size of billboards, but it grandfathers those erected before 1997.
[V., from GRANDFATHER CLAUSE.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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.