1)
What is the meaning of "ha'Mo'adah"?
1.
Rashi: They are designated special for this.
2.
Radak, Malbim: It is where [murderers] are No'adim (gathered). This [word form] is like (Yeshayah 30:32) Mosadah (foundation), from Mosdos (Yechezkel 41:8).