IFR student here, sometimes I listen on liveATC to comms traffic on various airports to check how well i can understand it. One call which I have heard multiple times was on Dallas Lovefield tower freq. telling departing aircraft: "RNAV Dorset Clear for take off " , to which pilots respond: "RNAV to Dorset clear for take off" . So to my knowledge this call refers to a GPS fix somewhere called dorset where the pilots shall proceed to after take off which is a part of departure procedure. I have been looking into all departure procedures for KDAL and could not find any fix named Dorset , or doorset (in case i have the spelling wrong) , I also tried to search for it on skyvector.com and couldn't find it. I think since I have the idea of SIDs right, I am not too worried about not knowing where that is, but it has been bugging me not knowing where that fix is. was wounding is there is someone regularly departing KDAL IFR might know.