widget- a component of a user interface that operates in a particular way
industrial-strength- very strong or powerful
module- any of a number of distinct but interrelated units from which a program may be built up or into which a complex activity may be analyzed
application- a program or piece of software designed and written to fulfill a particular purpose of the user : a database application
Much to my surprise I found all of these definitions using the Dictionary application on the Mac OS operating system.