泡 refers to bubbles, foam, or froth.
COMPOUNDS:
- 泡風呂: bubble bath
- 泡立てる: to whip, to foam
- 泡立て器: whisk
- 石鹸の泡: soap lather
IDIOMS:
- 泡を食う: to be flustered/panicked
- 泡と消える: to vanish like bubbles
- 水の泡: come to nothing, be in vain
- 泡銭: easy money (also written 泡銭)
SCIENCE:
- 気泡: air bubble (technical)
- 発泡: foaming, effervescence
- 発泡スチロール: Styrofoam