Translation guide
In Japanese, how you refer to your own grandfather versus someone else's, and how you address him directly, depends on formality, politeness, and family relationship. There are also general terms for elderly men.
The speaker is talking about their own grandfather to someone outside their family, or neutrally describing him.
Standard humble term used when speaking about your own grandfather to others. Not used to address him directly.
My grandfather takes a walk every morning.
The speaker is talking directly to their own grandfather in a casual, affectionate way.
The speaker is talking about the grandfather of the listener or a third person, showing respect.
Referring to any old man, not necessarily related.
Used in official documents, family registers, or very formal contexts.
Same as the humble term, but also the standard formal term for 'grandfather' in legal contexts.
おじいちゃん is intimate and should only be used for your own grandfather. Using it for someone else's grandfather can sound childish or disrespectful. Use おじいさん instead.
祖父 is humble and used for your own grandfather when speaking to outsiders. おじいさん is polite and used for someone else's grandfather or to address an elderly man. Within your family, you might call your grandfather おじいちゃん, but when talking to others about him, switch to 祖父.
Affectionate, familiar term used by children and adults to address their grandfather. Also used within the family to refer to him.
Grandpa, eat this.
More casual, slightly rough but still affectionate. Common among boys or in informal settings.
Hey Gramps, how are you?
Polite, somewhat formal. Can be used to address one's own grandfather, but sounds a bit distant or respectful. Also used to refer to someone else's grandfather.
Grandfather, have some tea.
Polite term for someone else's grandfather. Can also be used to address an elderly man politely.
Is your grandfather doing well?
Very polite, honorific. Used in formal situations or to show deep respect, often for someone else's grandfather.
Please give my regards to your grandfather.
Common, polite way to refer to an elderly man. Equivalent to 'old man' or 'grandpa' in a general sense.
That old man comes to the park every day.
Casual, sometimes blunt. Can be affectionate or slightly derogatory depending on context.
The old guy next door is noisy.
戸籍上の祖父
legal grandfather (on the family register)