吔 (yē) — (onomatopoeia) used to convey surprise, amazement, or a sigh

A casual interjection (not a real noun) used to show surprise, a sudden realization, or a light sigh — like 'wow', 'oh!', or 'ah'.

Most characters — around four in five — are built this way: one part hints at the meaning, the other at the pronunciation.

吔 combines 口 (mouth) with 也, which gives a sound clue.