See etymological and formal discussions s.v. dwkn. For various suggestions regarding the specific meaning of the form dktˀ at Hatra see DNWSI s.v.
Note that the nature of the sole JPA example (BR 34:1) and the single LJLA example (PJ Gen1:9) outside of material translated from Syriac suggests that this is not a normal western word, further supporting the etymological suggestion there discussed.