The term PhD is an academic title of doctor is granted to those who after completing a masters degree, continue the study to obtain the title of phd in any area, the most used in the English language.
The meaning of PhD has origin from the Latin Philosophiæ Doctor, meaning Doctor of Philosophy, or he who has love for knowledge, but does not mean that those who have a PhD are philosophers.
In reality, it is a reference to the ancient philosophers that were considered to be of the highest level of knowledge, competence in several areas and be references within the society.
So the title of PhD is not directly connected to philosophy and yes it is given to those who demonstrate a deep academic knowledge in some area, to the point of becoming expert in that subject.
Acronyms of the type PhD are also popularly used to refer to that person as it has a good knowledge in a certain area.
The PhD began to be used in Germany in the 19th century for those who especializavam in the area of human and soon after began to be adopted in countries such as the United States, who spread the application to other areas of knowledge.
The title of PhD is considered as the last step in higher education in the major universities of the world, although in some places, as in Brazil, is used in the abbreviation of doctor or phd that has the same meaning.
To be recognized as a PhD is very important to have an excellent academic career, with scientific papers recognized and a lot of experience in the area of operations.