1.
grandfather
One's grandfather or someone else's grandfather.
2.
elderly man, old man
An older gentleman.
おじいさん refers to grandfather or elderly men in general.
Formality levels
- おじいちゃん: grandpa (casual/affectionate)
- おじいさん: grandfather (polite)
- 祖父: grandfather (humble, formal)
- お祖父さん: grandfather (very polite)
Usage
1. One's own grandfather or someone else's
2. An elderly man in general
When addressing strangers, おじいさん can be used for elderly men but may be considered slightly rude in formal contexts.
Contrast with similar words
- おじいさん: grandfather / elderly man
- おじさん: uncle / middle-aged man
- おばあさん: grandmother / elderly woman
- おばさん: aunt / middle-aged woman
In folklore
昔話 (folktales) often begin with おじいさんとおばあさんがいました (There lived an old man and an old woman).
Related Words
Keigo:
祖父 (humble)
Related:
おばあさん (grandmother)
Compare:
おばさん (aunt / middle-aged woman)
Related:
おじ (uncle)
Compare:
おじいちゃん (grandfather)