Sam's shirt/jacket

So I finished off the pockets on Sam's birthday shirt/jacket last night, and did take those few snaps of the pockets to show here because I was so happy at how they turned out, but the light was not great for taking a photo of Sam modelling the whole thing.  So now it is, and I have.
It is made out of thin navy blue non-stretchy corduroy, using the old favourite Burda 7767 with a few modifications... the addition of two breast pockets with arrow head flaps, and the double welt/patch pockets I showed you yesterday.  And a curved hemline.  And I used brown snaps instead of buttons.  The collar facing, yoke facing, flap facings and welt pocket lining are all in a contrasting cotton, woven in a tiny plaid design of beige and black.
So here's the thing...  I don't know if it qualifies as a shirt or a jacket, or both.
It is made using a shirt pattern, and can be happily worn buttoned (snapped?) up and on its own... thus earning itself a "shirt" label.  
But also; being made of sturdy corduroy fabric, and also wearable unbuttoned and open over other shirts with his hands shoved in the pockets, it comes off as kinda jacket-style... thus attaining "jacket" status.
A hybrid.  
There must be a name to properly describe garments like this without having to resort to the hyphenated.

my tutorial for doing those combination welt/patch pockets just below