noun
Tehran
The capital city of Iran. Used as a proper noun; no special register or usage restrictions.
テヘランはイランの首都です。
Tehran is the capital of Iran.
来月、テヘランに出張します。
I'm going on a business trip to Tehran next month.
Standard katakana spelling for the Iranian capital; usually written in kana.
Ateji (phonetic kanji) spelling; rarely used and mainly of historical or stylistic interest.
From Persian تهران (Tehrân). The ateji spelling 第希蘭 is a phonetic rendering using kanji.