noun
Honorific or familiar term for one's uncle. 伯父さん is used for an uncle older than one's parent, and 叔父さん for a younger uncle, though the kana form おじさん is common for both.
伯父さんは父の兄で、大阪に住んでいます。
My uncle (older than my father) lives in Osaka.
おじさん、今度遊びに来てね。
Uncle, come visit us sometime.
noun
Familiar term for a middle-aged or older man, often used by children or in casual address. Can be used vocatively. Usually written in kana or katakana.
公園でおじさんが将棋を指している。
An old man is playing shogi in the park.
おじさん、この近くに駅はありますか？
Mister, is there a station near here?
noun
manybar goatfish
A species of goatfish (Parupeneus multifasciatus). Usually written in katakana as オジサン.
オジサンは熱帯の海に生息する魚です。
The manybar goatfish is a fish that lives in tropical seas.