The abbreviation Ph.D. stands for doctor of philosophy. In the United States, a Ph.D. is the highest degree that a person can earn in a particular subject.
Obtaining a Ph.D. typically takes four to eight years. During that time, a student may have two or three years of class work before writing a dissertation. While working on their Ph.D., a student spends a lot of time doing research and writing papers on behalf of the university at which they are enrolled. They may also spend time teaching undergraduate students. Those who obtain a Ph.D. may pursue a career with a university, government agency or non-profit organization, among many other options.