Difference between PolyLines and Splines.

Can someone explain the difference between Polylines and Splines please?
Do they have different applications? If so, what are those differences?

Jim,

here is a example of polyline: http://forum.librecad.org/Offset-feature-LibreCAD-tp5707006p5707009.html
Essentially they are lines and arcs as one entity.

Here is an example of spline: http://wiki.librecad.org/index.php/Spline_tutorial_1
splines are a mathematical way of expressing curves.

Ok, got it, thanks R.Van.