[Lazarus] What are "widgets" in lazarus?

[Bo Berglund]

I am switching from Delphi7-BDS2006 on Windows to FPC-Lazarus on
Windows with the aim of making cross-platform programs.
I also want to make one program run on an embedded ARM board running
linux for ARM.

So I have read a lot of the discussions here and asked questions about
setting up the environment etc.

One thing that bothers me is that I don't understand the term
"widget", which gets mentioned very often when discussion is about
screen output and the like....

What is a "widget" and how does it relate to my aim of making a
cross-platform program?

Is there a requirement for knowing which graphics card is going to be
used on the target machine if that is a Linux operating system?
If so how can anyone make a program that can run on any customer's
system and still not distribute the source code (which I do not want)?
I am assuming here that the graphics card is somehow sensed or similar
when the program is compiled on the target system.

Very confused because this has never popped up when I programmed for
Windows all these past 16-20 years....


-- 
Bo Berglund
Developer in Sweden