Shift Registers - How does one pronounce QH'
It's basically doing the function of "Serial Out", so you could call it that.

As written it would be "Q" "H" "prime". The ' is likely the prime symbol, something used for many different things, but in logic diagrams it typically indicates that something is a from a different state, or next clock cycle, or as the Wiki article puts it:


  x′ generally means something related to or derived from x