Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil in English-speaking countries and originally as Dr.Philos. (for the Latin philosophiae doctor or doctor philosophiae), is in many countries a postgraduate academic degree awarded by universities. The academic level known as a Doctorate of philosophy varies considerably according to the country, institution, and time period, from entry-level research degrees to higher doctorates. A person who attains a doctorate of philosophy may often be referred to as a doctor.
In the context of academic degrees, the term "philosophy" does not refer solely to the field of philosophy, but is used in a broader sense in accordance with its original Greek meaning, which is "love of wisdom". In most of Europe, all fields other than theology, law and medicine were traditionally known as philosophy, and in Germany and elsewhere in Europe the basic faculty of (liberal) arts was known as the faculty of philosophy. The doctorate of philosophy as it exists today thus originated as a doctorate in the liberal arts at the Humboldt University of Berlin, becoming common in large parts of the world in the 20th century. In many countries, the doctorate of philosophy is still awarded only in philosophy, i.e., liberal arts.