Closing windows NOT programs

Is there a keyboard shortcut to close a window instead of closing the entire program?

In windows it's alt + F4. Mac has apple + Q but that quits the entire program.

Is there a simple one to close just the current window?

Command(Apple)+W

As with Windows, you can easily see the keyboard shortcuts of most commands by checking out the menus of the Menu Bar. (kinda redundant ;p )