The Collaborative International Dictionary of English v.0.48:
Doctoral \Doc"tor*al\, a. [Cf. F. doctoral.] Of or relating to a doctor, or to the degree of doctor. [1913 Webster] Doctoral habit and square cap. -- Wood. [1913 Webster]WordNet (r) 3.0 (2006):
doctoral adj 1: of or relating to a doctor or doctorate; "doctoral dissertation"; "doctorial candidates" [syn: doctoral, doctorial]