noun
The basic modern meaning: a hollow cylindrical object or container, such as a cardboard tube, bamboo tube, pipe-like shape, or cylinder.
ポスターを丸めて筒に入れた。
I rolled up the poster and put it in a tube.
竹の筒に水を入れて運んだ。
They carried water in a bamboo tube.
noun
gun barrel; barrel of a firearm
A firearm or cannon barrel viewed as a hollow tube. In modern precise language, 銃身 or 砲身 is often clearer, but 筒 can appear in older, descriptive, or less technical wording.
鉄砲の筒を人に向けてはいけない。
You must not point the barrel of a gun at people.
noun
Old-fashioned or historical use in which 筒 refers to the firearm or cannon itself, not just the barrel. Modern Japanese normally uses 銃, 鉄砲, or 大砲.
古い記録では、筒が鉄砲や大砲を指すことがある。
In old records, 筒 can refer to a gun or cannon.
noun
well lining; well curb
Obscure construction-related use for the cylindrical lining or curb of a well. It is limited and much less common than the general 'tube' meaning.
井戸の筒とは、井戸の内側を支える囲いのことだ。
A well's 筒 is the lining or curb that supports the inside of the well.
Also means a tube or pipe, but 管 often emphasizes a conduit for liquids, gas, wires, or bodily vessels, while 筒 more strongly suggests a hollow cylindrical shape or container.
A more geometric or technical word for a cylinder; 筒 is the simpler everyday word for a tube-like object.
The standard modern term for a gun barrel; 筒 in this sense is less precise and can sound older or descriptive.
A specific word for a well curb or well frame; it is more explicit than the rare well-related use of 筒 alone.
The historical derivation of つつ is uncertain here. The kanji 筒 is conventionally associated with hollow cylindrical tubes and related objects.