[jondubois]

I guess it's not broadly used terminology but it was common when I was at uni: http://mnemstudio.org/path-finding-a-star.htm - It's basically a list which you use to hold nodes which you haven't visited yet and you expand them in-place and pop them off as you visit them.

[pmiller2]

Oh, right, like the "seen but not visited" set you maintain when doing BFS.