Doctor of Philosophy, abbreviated Ph.D., means "teacher of philosophy". PhD for the Latin Philosophy Doctor is an advanced academic degree awarded by universities. In some (but no all) countries in the English-speaking world, Ph.D. has become the highest degree one can earn (for more information, see also the Higher doctorates awarded by universities in Ireland, UK and some Commonwealth countries) and applies to graduates in a wide array of disciplines in the humanities and sciences. This degree has become a requirement for a career as a university researcher or professor in many fields. Additionally, many Ph.D. graduates go on to careers in NGOs (non-governmental organizations), in the private sector or in government departments.
The detailed requirements for award of a Ph.D. degree are varying throughout the world, but there are a number of common factors applying to all universities. Firstly, the candidate must submit a dissertation or thesis consisting of a suitable body of his original academic research, which is in principle worthy of publication in a peer-refereed context. In many cases a candidate must defend his work before a panel of expert examiners appointed by the university. In some countries, the research is examined by a panel of expert examiners who stipulate whether the research (or dissertation) is in principle passable and the issues that need to be addressed before the dissertation can be passed. Usually, there is a prescribed minimum period of study (two to three years full time typically), which must take place before submission of the thesis. This requirement is usually waived for academic staff who submits a portfolio of peer-reviewed published work.
There also may be some obligatory additional, advanced courses relevant to the area of specialization of the candidate, which he or she may be required to successfully complete. In some countries like the US, Denmark, Canada, most universities require coursework for Ph.D. degrees. In other cases, especially in countries which have a greater degree of specialization at the undergraduate level (UK, for example), there is no such condition in general. It also is not uncommon for several individual universities or departments to specify analogous requirements for students no already in possession of a master's degree. Additionally, universities in the non-English-speaking world have begun adopting some similar standards to those of the Anglophone Ph.D. for their research doctorates.