What is the definition of "Ir Chomah"?
Rashi: It is a town that had a surrounding wall from the days of Yehoshua bin Nun. 1
At the time of conquest (See Sifsei Chachamim).
What distinction does the Pasuk draw between the sale of a field and the sale of a house in a walled town?
Rashi: Whereas the former may redeem his field after two years, the latter may only redeem his house during the first year, but not afterwards.
Why does the Torah add the 'Vav' at the end of "Sh'nas Mimkaro"?
Targum Onkelos and Targum Yonasan: It implies a full year from day to day, and not until the end of the year (Erev Rosh ha'Shanah). 1
Torah Temimah (citing Erchin, 18b): Because it implies "Mimkaro", 've'Lo Shanah shel Minyan' Olam'.
What is the meaning of "Yamim" (on its own)?
Why does a house in a walled town not revert to its original owner like a field?
Ramban: Because once the owner fails to redeem it in the first year, he finds himself a new place of residence, and his old abode is no longer of any use to him.