Cylinder
Tube, Pipe
トウ
つつ
管 （カン、くだ） Pipe
筒 （トウ、つつ） Cylinder, Tube, Pipe
The 筒 kanji means Cylinder, but the 筒 word can also mean Pipe.
Bamboo 竹 stalks are hollow Cylinders 筒. They're the same 同じ shape!