Darth Vader pencil drawing

So I guess I've got a Star Wars theme going here: Kylo Ren, a stormtrooper, and Boba Fett. So it wouldn't be complete without a portrait of Darth Vader! It is very interesting to see how a character that is completely black turns out to actually be all different values reflecting more light than would be expected.
So is this a sketch or a drawing? Although this is not on high quality drawing paper, it did start out as a sketch in my sketchbook. But as I added in more finishing touches, I think it developed more into a drawing. Is there a time limit on a sketch? I once read that sketches are less than an hour, and since his took a couple hours (it's hard to tell exactly since this was three different short sittings), I am going to call it a drawing.
It seems like today's trend is to be ultra-realistic, but that is definitely not my style. I love being able to see the strokes of the artist, or pencil lines in this case. I'm sure I could go in with a blending stump and remove all of the lines (if my sketchbook paper could handle it) but I think leaving it the way it is gives it character and movement within the portrait.