The word “doctor” can refer to a person with the highest academic degree, i.e., a doctorate. It is pronounced as /ˈdɒktə(r)/. For example, “He is a doctor of philosophy.” Another word “Ph.D.” is also used to denote a doctorate. It is pronounced as /ˌpiː eɪtʃ ˈdiː/. As in “She holds a Ph.D. in biology.” These are common ways to refer to someone with a doctoral degree.