R mtcars dataset, meaning of "vs" variable?

I think it's whether the car has a V engine or a straight engine. I'm basing this on the foot note on the page numered 396 of http://www.mortality.org/INdb/2008/02/12/8/document.pdf

Binary variable signaling the engine cylinder configuration as either:

V-shape (vs=0) or Straight Line (vs=1)

Configuration offers trade offs in power/torque, design usage in terms of space/size of engine and performance or center of gravity of vehicle. The geometry and placement of the engine, as influenced by its cylinder head, can have numerous knock-on influences on the vehicle beyond the technical engineering considerations of the cyliner angle.