Unix: How to unsplit in screen

I'm trying to learn how to use screen, in unix so that I don't have to open up several ssh connections and terminal windows just because I want to do more than one thing at the same time on a machine. I have found the split command quite useful, but I have a problem I can't seem to figure out of... how do I unsplit??

I can split split using ^A S and switch between them using ^A ^I, but can't figure out how to remove a split...

ctrl-a,X doesn't work on my distribution either.

If you go into the help by pressing ctrl-a,?, you may notice that there is no remove command listed. (This is the case on my distribution, for some reason). Note that this means there is no keybinding for the command, but the command should still work using the "long form" that maxelost suggested.

Don't worry, you can still remove the current split using "long form": ctrl-a:removeenter.

In addition, you can bind the remove command to X by putting this line in your ~/.screenrc file (and then restarting screen so the changes take effect, of course):

bind X remove

Just use ctrlaQ (given that a is your screen-command key) to close all splits. ctrlaX closes only active window, as maxelot commented.

For example this page documents screen splitting, and other useful keys for screen.