아

1. oh; ah
An exclamation uttered when the speaker expresses his/her surprise, embarrassment, impatience, or urgency.

2. oh; wow; ah
An exclamation uttered when the speaker expresses his/her delight or excitement.

3. oh; aww; oh no
An exclamation uttered when the speaker expresses the feelings of worry, anxiety, regret, or lamentation.

4. umm; ahem
An exclamation uttered before the speaker begins his/her words when he/she talks to someone or attracts someone's attention.

5. oh; aha; oh yeah
An exclamation uttered when the speaker realizes something he/she did not know.