膨らむは英語で
to inflate

英語の定義

膨らむ
1. v. to swell, to expand, to get bigger
2. v. Usage: The intransitive verb is used to describe something that happens naturally of its own accord, generally with a positive sense.
Usage: * 蕾が膨らむ、夢が膨らむ、胸が〔幸せなどで〕膨らむ - the buds swell, one's dreams grow bigger, one's chest swells with joy, etc.
3. v. Usage: The synonym 膨れる is used to describe something that happens due to an abnormality or external force, not necessarily with a positive sense.
Usage: * パンが膨れる、躯が膨れる、頬が膨れる - the bread rises, the corpse bloats, one's cheeks puff up (→ one pouts or sulks)