What does 通 mean?
通 is a Japanese noun meaning “authority; expert; connoisseur; well-informed person” in English. It can also be translated as “counter for messages, letters, notes, documents, etc., understanding (esp. of male-female relations), supernatural powers” depending on context. It is written as 通 in kanji, つう in hiragana, and tsuu in romaji. This word is part of JLPT N4 vocabulary.
Example sentences
コーヒー通の人達に結構評判がいいそうです。
I hear that it has quite the reputation with coffee connoisseurs.
ここにあなたあての手紙が何通かあります。
Here are some letters for you.