dialogue box
or dialog box
n (Computer Science) computing a window that may appear on a VDU display to prompt the user to enter further information or select an option
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014