封筒
ふうとう
fuutou
= envelope
封筒 combines the act of sealing (封) with the image of a tube or cylinder (筒) — a word that captures the very purpose of an envelope: to close something safely inside. In Japan, choosing the right 封筒 for the occasion is a quiet but meaningful social act.
封筒 (fuutou) means ‘envelope’ — the paper sleeve used to enclose letters, documents, cards, or cash. The verb 封をする (fuu o suru) means ‘to seal,’ making 封筒 literally ‘a tube that is sealed.’ Japanese envelopes come in standardized sizes: 長形封筒 (nagagata fuutou) are long, narrow envelopes suited for standard letters and official documents, while 角形封筒 (kakugata fuutou) are square or rectangular and used for larger papers, brochures, or multiple sheets. In formal contexts such as job applications or government correspondence, the choice between 長形 and 角形, as well as the color (white vs. brown), signals the nature of the contents.
Be careful not to confuse 封筒 with 袋 (fukuro), which is a general bag or pouch. 封筒 specifically refers to the flat paper envelope used for correspondence or cash gifts, not bags used for shopping or storage. When addressing a formal 封筒 in Japanese, the recipient’s name goes on the front center and your own name and address on the back flap — the opposite layout from many Western envelopes. For cash envelopes at ceremonies, never reuse a 封筒; a fresh, unwrinkled envelope signals respect.
封 (fuu) carries the meaning of ‘to seal’ or ‘to close,’ derived from the idea of an official seal pressed onto a closure. 筒 (tou) means ‘tube’ or ‘cylinder,’ evoking the hollow shape that holds the contents. Together, 封筒 describes an object whose defining feature is both its tubular form and its sealable opening — a shape and function rolled into one word.
Everyday use
手紙を書いたら、封筒に入れて封をした。
Tegami o kaitara, fuutou ni irete fuu o shita.
Once I finished writing the letter, I put it in an envelope and sealed it.
Casual / Social Media
友達の誕生日カードを封筒に入れて、明日ポストに投函するつもりです。
Tomodachi no tanjoubi kaado o fuutou ni irete, ashita posuto ni touukan suru tsumori desu.
I’m planning to put my friend’s birthday card in an envelope and drop it in the mailbox tomorrow.
Formal / Cultural context
結婚式のご祝儀は、白い祝儀袋（封筒）に入れて、水引を結んで持参するのがマナーです。
Kekkonshiki no goshuugi wa, shiroi shuugibukuro (fuutou) ni irete, mizuhiki o musunde sansuru no ga manaa desu.
For a wedding gift of cash, it is proper etiquette to place the money in a white ceremonial envelope, tie it with a mizuhiki cord, and bring it in person.
Japan has a distinct culture of presenting cash in specially designed 封筒 called 祝儀袋 (shuugibukuro) for celebratory occasions and 不祝儀袋 (bushugibukuro) or 香典袋 (koudenbukuro) for funerals and condolences. These are not ordinary envelopes — they are ornate paper constructions decorated with 水引 (mizuhiki), intricately knotted cords in symbolic colors. For weddings, the cords are tied in a bow that cannot be undone (結び切り, musubi-kiri), signifying that the happy event should happen only once. For birthdays or new year’s gifts, a bow that can be retied (蝶結び, choumusubi) is used, expressing the hope that the joyful occasion will come again.
The act of sealing and opening a 封筒 carries its own etiquette in Japanese correspondence. Opening a formal letter carelessly — tearing the flap roughly — is considered disrespectful to the sender’s effort. Letter openers (レターオープナー) are a practical tool in offices for this reason. When sending a formal document, many Japanese senders write 〆 or 封 in ink across the sealed flap, an old-fashioned mark confirming the envelope was properly closed by the sender and has not been tampered with.