grandfather

American  

[gran-fah-ther, grand-] / ˈgrænˌfɑ ðər, ˈgrænd- /

noun

1. the father of one's father or mother.

2. a forefather.

3. 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.

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verb (used with object)

1. 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.

grandfather British  

/ ˈɡrænd-, ˈɡrænˌfɑːðə /

noun

1. the father of one's father or mother

2. (often plural) a male ancestor

3. (often capital) a familiar term of address for an old man

4. dialect a caterpillar or woodlouse

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Etymology

Origin of grandfather

late Middle English word dating back to 1375–1425; grand-, father

Explanation

Your grandfather is the father of one of your parents. If your grandfather is quite old and has dozens of grandchildren, it might be hard for him to remember your birthday every year. Everyone has two biological grandfathers, whether they've had the chance to know them or not. In some families, grandmothers and grandfathers are involved in raising and caring for their grandchildren, while in others a grandfather may have died or live very far away. Informally, a grandfather can also be someone who started or invented something: "Blues musician Robert Johnson was the grandfather of rock and roll."

Example Sentences

The search engine was important, Rainer said, not only for what it told him about his grandfather, but because it also helped clear other members of his family, including his father.

From BBC • Apr. 14, 2026

Kani thinks about his role in this production somewhat like his role as a grandfather.

From Los Angeles Times • Apr. 14, 2026

Rainer never met his grandfather, who died shortly before he was born in 1961.

From BBC • Apr. 14, 2026

Among its residents: the mother, father, grandmother and grandfather of an ASU undergrad.

From MarketWatch • Apr. 10, 2026

“My book tells me that it’s a grandfather clock,” explained C.C.

From "The Very, Very Far North" by Dan Bar-el

Related Words

• ancestor
• grandpa
• patriarch