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; see origin at 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

In a September, 2016, email to his brother, Mark, he wrote, “whtchoo want me toodo — bust out crying” in response to news that their cousin had become a grandfather.

From Los Angeles Times • May 6, 2026

His grandfather Antonio is revealed as a traveling merchant who operated between Catalan Spain and Morocco, rather than simply a farmer.

From Science Daily • May 4, 2026

Edward “Ted” Crosby Johnson, who founded Fidelity Management & Research in 1946, and grandfather of FMR’s current CEO, Abby Johnson, worked as a lawyer at Ropes & Gray.

From Barron's • May 1, 2026

A Visit To Grandpa's follows a young boy sent to spend a summer full of adventure with his eccentric grandfather on a Welsh farm.

From BBC • Apr. 30, 2026

‘My grandfather once got close to the Mountain,’ he’d explained when Torak had woken him in the night.

From "Wolf Brother" by Michelle Paver

Related Words

• ancestor
• grandpa
• patriarch