The proper word is 鉈 "nata". You have different versions of this tool:
- the one in the link by 87Burban is a 腰鉈 koshi-nata, meaning "worn at the hip", a general use hatchet (also万能鉈 bannô-nata)
- 竹割り鉈 takewari-nata, a nata for splitting bamboo (this one often comes w/o a wooden handle)
- 剣鉈 ken-nata, literally "sword-nata", is a clip point nata mostly used by hunters
- there are more, shapes (eg. with a blunt nose or sharp hook at the end of the blade like a bill hook) and names
Most nata are chisel-ground for right hand use (unlike some tactical knives *cough*Emerson*cough*), meaning it works very well with little practise. This also makes sharpening easy, since you only have to sharpen the bevel on the right side and then just knock off the burr on the flat (or often slightly hollow-ground) left-hand side.
Most takewari-nata have a standard two bevel grind, if that's you want.
Ookami