Board Thread:Speculation House/@comment-64.189.84.174-20150118174835/@comment-4010415-20150118193504

In the flashback, when Qrow shows up, that same symbol is in the background behind him, except flipped horizontally. So, my theory is, either

1. It's Qrow's symbol.

2. It's Raven's symbol, and their symbols put together form a pair of winged eyes with gears in them, symbolizing the fact that they're siblings. (An edit by Montyoum in 2013 shows Qrow's last name might be Branwen)