The kanji 筒筒 primarily means "tube," "pipe," or "cylinder." It refers to a hollow, cylindrical object or container. This core meaning extends to various applications, from simple physical objects to more abstract concepts.

・On-yomi (音読み): トウ (tō) ・Kun-yomi (訓読み): つつ (tsutsu)

⚫︎望遠鏡 (ぼうえんきょう) Translation: Telescope (literally, "distant-viewing tube") ⚫︎煙突 (えんとつ) Translation: Chimney (literally, "smoke tube") ⚫︎筒抜け (つつぬけ) Translation: Leaking; being completely informed (literally, "tube through," implying information passing directly through)

The kanji 筒筒 is a pictograph. The left side represents a bamboo stem. The right side represents something being contained inside the bamboo. This visual representation conveys the idea of a hollow tube or cylinder, much like a bamboo stalk. The bamboo connection is significant because bamboo has historically been used to make tubes, pipes, and containers in East Asia.