modal particle, onomatopoeia · (Tw) sentence-final particle used to convey a friendly tone when giving an admonition or correcting someone

要小心喔！

onomatopoeia · (interjection) oh; I see (used to indicate realization, understanding)

喔，原来是这样。

onomatopoeia · onomatopoeic sound of a rooster's cry, often used in the reduplicated form 喔喔 wō​wō

公鸡喔喔地叫，预示着新的一天开始了。