I see the term Crow used in this forum, what does it mean?

It's what you eat when you make a bold proclamation without facts and end up being wrong. Happens here daily.

Oooooo... I saw a guy crow the other day at the flying field. I couldn't tell you exactly what it is, but it looked really strange when he had to use it while landing. I think it opened both the aileron and flaps at the same time and killed/neutralized the lift that the aircraft was receiving because of a huge head wind at the time. After the landing he showed me what crow looked like on the aircraft, but I didn't quite understand what it was actually used for...

Crow or butterfly is mixing flaps, ailerons and elevator together to basically use as dive brakes. Ailerons are up, flaps down with a little bit of down elevator. put the plane into a full vertical dive at engine idle, and the plane will not gain any speed. pull up at ten feet and land. pretty cool, just set up an ultra stick and playing with it now.

Yeah! That's what I saw... No way in hell was I going to be able to explain it like that (i'm new to the hobby), but it looked really cool when it was used.

It can also be 2 piece rudder or 2 piece ailerons which split open on command.

It's used a lot on sailplanes. A good state of the art sailplane is so aerodynamically clean that without either spoilers or crow, they are almost impossible to land. Put the nose down a few degrees to steepen the glide slope and the plane just speeds up like a car coasting down a hill and trying to flare just causes the plane to balloon back up in the air.