Each house; referring to houses one by one (each household).
古い町並みを一軒一軒見て回った。
I went around looking at the old houses one by one.
彼は一軒一軒訪ね歩いてチラシを配った。
He went door to door and handed out flyers.
引っ越し先ではご近所に一軒一軒挨拶するのが礼儀だ。
When you move house, it's polite to greet each neighbor house by house.
House to house; door to door (adverb describing going from one house to another).
募金活動で学生たちは一軒一軒回って寄付をお願いした。
For the fundraising drive, the students went door to door asking for donations.
セールスマンが一軒一軒商品を見せて回った。
The salesman showed the product door to door.