the founder or originator of a family, species, type, etc.; the first of one's or its kind, or the one being longest in existence: the grandfather of all steam locomotives.
to exempt (something or someone) from new legislation, restrictions, or requirements: The law grandfathered all banks already operating at the time of passage. He was grandfathered into the pension plan.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use grandfather in a sentence
These can be grandfathered down from generation to generation.
Plans bought before the ACA passed are grandfathered in, but newer plans are subject to the whims of insurance companies.
Even in fear of possible danger to be incurred, woman must no longer be "grandfathered."The Truth About Woman | C. Gasquoine Hartley
British Dictionary definitions for grandfather
the father of one's father or mother
(often plural) a male ancestor
(often capital) a familiar term of address for an old man
dialect a caterpillar or woodlouse
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012