Counter-like noun for a single document, letter, or similar item. Often used with 書類, 手紙, はがき, etc.
申込書を一通提出してください。
Please submit one copy of the application form.
昨日、友人から手紙が一通届いた。
I received one letter from a friend yesterday.
Abbreviation of 一方通行. Used in traffic contexts; may appear on signs or in casual speech.
See also: 一方通行
この道は一通だから、入れないよ。
This road is one-way, so you can't enter.
pure straight; 1-9 straight
Mahjong term: a winning hand with tiles 1 through 9 of the same suit. Abbreviation of 一気通貫. Sometimes written in katakana as イッツー.
See also: 一気通貫 (いっきつうかん)
彼は一通を上がって逆転した。
He won with a pure straight and turned the game around.
I wrote one letter of thanks.
This street will become one-way starting next month.
I won a mangan hand with a pure straight.
Please send one copy of the contract.
一方通行 is the full, formal term for one-way traffic, while 一通 is its casual, shortened form often seen on signs.
一気通貫 is the full mahjong term for the 1-9 pure straight hand, while 一通 is its common abbreviation.
一通 (いっとう) means 'one copy/letter' of a document, while 一通り (ひととおり) is an adverbial noun meaning 'roughly' or 'in general' despite the shared kanji.
Standard kanji spelling for all senses.
Katakana spelling sometimes used for the mahjong term.
Compound of 一 (one) and 通 (counter for documents/letters). The traffic and mahjong senses are abbreviations of longer terms.