godan verb (-su), transitive verb
Transitive: cook or heat something with steam. Common with vegetables, dumplings, towels, etc.
See also: 蒸かす
野菜を蒸して食べると甘みが増す。
Steaming vegetables brings out their sweetness.
蒸
I warm my face with a steamed towel.
godan verb (-su), intransitive verb
be hot and humid; be sultry
Intransitive: describes muggy, oppressive heat, often in summer or in a closed room.
今日は朝から蒸して、汗が止まらない。
It's been hot and humid since this morning; I can't stop sweating.
部屋が蒸しているから窓を開けよう。
The room is stuffy, so let's open a window.