火口

Etymology 1
Compound of.

Noun

 * 1)  a crater
 * 2) the firedoor of a boiler

Etymology 2
Compound of.

Noun

 * 1) the origin of a fire
 * 2) an opening for ignition
 * 3) the nozzle of a welder, etc
 * 4) the opening through which the fire enters the barrel in a hinawajū
 * 5)  a crater

Etymology 3
Compound of.

Noun

 * 1) tinder
 * 2) a place for setting a fire