The Doctor of Philosophy (PhD or DPhil) is the highest academic degree awarded across a wide range of disciplines, representing the pinnacle of graduate study and original research. To earn this terminal degree, candidates must produce a substantial dissertation of original research that expands existing knowledge, often defending it before a panel of experts. Intriguingly, the "philosophy" in its name refers to the ancient Greek "love of wisdom," historically encompassing most academic subjects outside of theology, law, and medicine. Successful completion of a PhD is typically required for careers as university professors or researchers, and graduates are entitled to use the prestigious title of "Doctor."