In this respect, probably nothing, and they probably all mean Q. Q is a different language to K, implemented in K. There are more versions of K than Q- kdb+ is

In this respect, probably nothing, and they probably all mean Q. Q is a different language to K, implemented in K. There are more versions of K than Q- kdb+ is the only Q implementation, but there are others like shakti, ngn/k, and kona that implement K.