• (British) IPA: /ˈɡɹæn(d)ˌfɑːðə(r)/
  • (RP) IPA: /ˈɡɹænˌfɑːðə/
• (GA) enPR: grănd′fä'thər, IPA: /ˈɡɹæn(d)ˌfɑðɚ/, [ˈɡɹ̠(ʷ)ẽˑə̯̃n(d)ˌfɑˑðɚ]

grandfather (plural grandfathers)

1. A father#Noun|father of someone's parent#Noun|parent. [from 15th c.]

   Synonyms: Thesaurus:grandfather

   Antonyms: grandmother, grandchild, granddaughter, grandson, Thesaurus:grandmother

   • 1766, William Blackstone, “Of Title by Descent”, in Commentaries on the Laws of England, book II (Of the Rights of Things), Oxford: Printed at the Clarendon Press, OCLC 65350522 ↗, page 203 ↗:

     Lineal conſanguinity is that which ſubſists between perſons, of whom one is deſcended in a direct line from the other: as between John Stiles (the propoſitus in the table of conſanguinity) and his father, grandfather, and great-grandfather, and ſo upwards in the direct aſcending line; or between John Stiles and his ſon, grandſon, great-grandſon, and ſo downwards in the direct deſcending line.

2. (by extension) A male forefather.

   Synonyms: highfather, grandsire

• French: grand-père, aïeul
• German: Großvater, Grossvater (Switzerland and Liechtenstein), Opa, Opi; Großvater väterlicherseits (paternal), Großvater mütterlicherseits (maternal)
• Italian: nonno
• Portuguese: avô
• Russian: де́душка
• Spanish: abuelo

• French: aïeul
• Portuguese: avoengo
• Spanish: abuelo

grandfather (grandfathers, present participle grandfathering; past and past participle grandfathered)

1. (transitive) To be, or act as, a grandfather to.

grandfather (grandfathers, present participle grandfathering; past and past participle grandfathered)

1. (transitive, chiefly, US, law) To retain existing#Adjective|existing laws or rule#Noun|rules for (a person or organization previously affect#Verb|affected by them). [from 1950s]
2. (intransitive, chiefly, US, law) To retain existing laws or rules only for people or organizations previously affected by them, and to apply new laws or rules to the unaffected people or organizations. [from 1950s]