(Education) a doctorate
awarded for original research in any subject except law,
medicine, or theology. Abbreviation: PhD or DPhil
——Collins English Dictionary – Complete and Unabridged ? HarperCollins Publishers 1991, 1994, 1998, 2000, 2003的釋義
a doctor's degree awarded for advanced studies in the humanities or the social, behavioral, or pure sciences
——Random House Kernerman Webster's College Dictionary, ? 2010 K Dictionaries
Ltd. Copyright 2005, 1997, 1991 by Random House, Inc.的釋義
第壹種釋義的重點是：除了法學、醫學或神學外的博士學位；
第二種釋義的重點是：人文學科（歷史、哲學、文學等）、社會學、行為科學或者理科博士。
所以，個人認為翻譯為博士較好。