A skateboarding trick that is often called a boardslide, but if you know the history of the move, it is easy to differentiate between the two.
Back in the 60's and 70's, before people skated rails and ledges, they skated halfpipes and bowls. If you wanted to do a boardslide/lipslide, you would ride up the side of the vert, and get one of your trucks over the lip, slide sideways a little ways, and then probably drop back in. This is where the difference in nomenclature comes in.
If you lifted your front truck up as you approached the lip, and slid, you did a boardslide. If you spun a 180 quickly, and had your rear truck above the lip, that was a lipslide. This is still the standard used today. That is, if the rear truck is lifted over the object, it's a lipslide. Front truck, it's a boardslide.
Of course, some old-schoolers don't call it a lipslide unless there is a lip, as in that of a halfpipe or bowl. I tend to disagree, because having more and more complicated names for tricks is entertaining.