Routledge Encyclopedia of Philosophy Online, or REP Online, is a dynamic online resource for researching, teaching and studying philosophy and related disciplines. Discover articles ranging from Medieval philosophy to Postmodernism, and from Aesthetics to Philosophy of biology.
The SEP was designed so that each entry is maintained and kept up to date by experts in the field. This dynamic reference work maintains academic standards while evolving and adapting in response to new research.
The Internet Encyclopedia of Philosophy (IEP) was founded in 1995 to provide open access to detailed, scholarly information on key topics and philosophers in all areas of philosophy.
The aim of this dictionary is to provide teachers, students and laymen interested in philosophy with clear, concise, and correct definitions and descriptions of the philosophical terms, throughout the range of philosophic thought. In the volume are represented all the branches as well as schools of ancient, medieval, and modern philosophy.
Dictionary of World Philosophy by 
The Oxford Dictionary of Philosophy by