ㅇ
이응 (ieung)
Silent at the start of a syllable — it just holds the place. At the end, it's “ng” as in “sing.”
StrokesOne stroke: a circle, started at the top and drawn counterclockwise.
Easy to confuseㅎ — ㅎ is ㅇ with a hat — a dash and a line on top — and sounds like h.
Examples
아이
ai
child
강
gang
river
공항
gonghang
airport