Psychology Dictionaries, Glossaries, and Encyclopedias

The following are various dictionaries, glossaries, and encyclopedias related to psychology, psychiatry, and associated disciplines. As I write or come across other useful reference resources, I will add them to this list. If you notice that any of the links don't work (or, worse yet, that any sites require a fee!), please send me a short note.


The information provided by the following sites is for educational purposes only and does not replace discussions with and/or diagnoses by appropriate healthcare providers. If you or someone you know is experiencing difficulties of a psychological nature, see your family physician (alternatively, see the Professional Associations section of my Psychology Resources links, which provides phone numbers of organisations that will be glad to direct you to the appropriate resources).

Note that some of the dictionaries cover psychological terms, some cover psychiatric terms, and some cover both. Just so we're all on the same page, take a moment to familiarise yourself with the definitions of and difference between "psychology" vs. "psychiatry".

AlleyDog Psychology Glossary
Over 700 easy-to-understand definitions for those learning psychology. Covers a lot of different areas—even evolutionary psychology! All terms checked for accuracy before inclusion in the database. I use this with PsyBox's dictionary, which is just as extensive (but which seems to cover some more technical and obscure terms, which I like) and with the much larger and more detailed Gleitman glossary (which is great, but may not stay free for too long).

AllPsych Psychology Dictionary
(Christopher L. Heffner, PhD)
Briefly defines over 500 psychology-related terms.

Alphabetical Glossary of Psychological Terms

Despite the name, this glossary covers primarily psychiatric terms. It focusses on basic, common terms—as does the Glossary of Psychiatric Terms, from Saunders' Pocket Essentials of Psychiatry. For a much more extensive glossary, see John Abess's Glossary of Psychiatric Terminology.

Anxiety Disorders Glossary
(Anxiety Disorders Association of America)
Helpful glossary covering terms related to fear, anxiety, and anxiety disorders.

BehaveNet Glossaries
Glossaries related to specific topics in psychology: addiction; chronobiology; diagnoses (including DSM disorders); drugs, EEG; forensic; HIPAA; memory; notable people; pharmacology; psychopathology; the psychotherapies (Adlerian, cognitive, EMDR, family, gestalt, internal family systems, Jungian, narrative, psychoanalytic, psychodynamic, transactional analysis); and sleep. Also includes a glossary of acronyms and abbreviations.

Biological Timing Glossary
(Liz Hunter, Jim Yurasits, Marjorie Maxey)
Brief glossary covering terms related to biological clocks and biotiming.

Deviants' Dictionary
This is a most comprehensive encyclopedic dictionary of BDSM-related terms. Medical Terms
From this site, receive terms from:

Dream Dictionary
Provides detailed explanations of various dream subjects in order to help you explore, interpret, and (try) to understand your dreams.
(from Columbia Encyclopedia, Sixth Edition) or
When I need fast access to brief articles on psychology, I look here after I look at Wikipedia, the Gale Encyclopedia of Psychology, and the Gale Encyclopedia of Childhood and Adolescence. 57,000 frequently updated articles, most with useful bibliographies as well.

Encyclopedia of Informal Education
Although this encyclopedia focusses on key ideas, practices, and thinkers in informal education and lifelong learning, it can also be used as a general resource in psychology, covering such varied topics as: adult education, Aristotle, authenticity, boys' clubs, Martin Buber, Mary carpenter and reformatory schools, Christian informal education, coffee houses, colonialism, community and communitarianism, community development, communication education, competence, crime and informal education, curfews, curriculum theory, John Dewey, Charles Dickens, educational gerontology, experiential learning, friendship, Erich Fromm, full-service schooling, Howard Gardner and multiple intelligences, girls' clubs, holistic education, Ivan Illich, Jewish informal education, Jiddu Krishnamurti, leadership, learning theory, Kurt Lewin and field theory, Karl Marx, mentoring, Lily Montagu, Maria Montessori, Plato, post-modernism, race and difference, ragged schooling, reflection, information education and residential work with adults, Carl Rogers, Rousseau, self direction, social capital, summer camps, sunday schools, supervision, tacit knowledge, theories of action, training informal educators, vocation and calling, and youth.

Gale Encyclopedia of Childhood and Adolescence
(Edited by Jerome Kagan, Harvard University)

Search via
Nearly 700 overview essays on "the primary stages, key theories, and issues in child development, and definitions of terms and concepts related to the health care, education, and developmental psychology of children." Search the encyclopedia by entering your terms at the bottom of the screen (make sure you have selected to search "this publication"). I use this in conjunction with the Gale Encyclopedia of Psychology, Wikipedia, and Sometimes you will get an error message when searching; just repeat the search.

Gale Encyclopedia of Psychology
(Edited by Bonnie B. Strickland, PhD)

Search via
More than 1,500 great overview articles covering all areas of psychology and offering key references for further research. Also includes nearly 400 biographies. Search the encyclopedia by entering your terms at the bottom of the screen (make sure you have selected to search "this publication"). I use this in conjunction with Wikipedia,, and the Gale Encyclopedia of Childhood and Adolescence. Sometimes you will get an error message when searching; just repeat the search.

Glossary of Behaviorism Terms ("Glossary '57")
(William S. Verplanck, University of Tennessee)
A very useful glossary of terms related to the objective science of behaviour. If the site has moved, try Use in conjunction with The Glossary of Terms for the Experimental Analysis of Behavior.

Glossary of Consumer Behavior Terms
(John Mowen and Michael Minor)
Excellent glossary with over 700 terms relating to: consumer behavior, conditioning and learning, perception, social psychology, attitudes, and persuasion.

Glossary of Freudian Terminology
(Doug Davis, Haverford College)
Simple glossary covering key terms in Freudian psychoanalytic theory.

Glossary of Freudian Terms
(Craig Chalquist, PhD, Author of The Tears of Llorona:
A Californian Odyssey on El Camino Real
More extensive and detailed than the Davis glossary.

Glossary of Jungian Terms
(Craig Chalquist, PhD, Author of The Tears of Llorona:
A Californian Odyssey on El Camino Real
Extensive, detailed glossary covering terms related to Carl Jung's theories of personality and therapy.

Glossary of Psychiatric Terminology
(John F. Abess, MD, Charleston, SC)
A superb, extensive glossary of psychiatric terminology. I use this in combination with the shorter Glossary of Psychiatric Terms (see below), from Saunders' Pocket Essentials of Psychiatry, which defines the terms most commonly used in psychiatry. I also use it in combination with the Alphabetical Glossary of Psychological Terms, from, which, despite its name, covers more psychiatric terms than psychological ones.

Glossary of Psychiatric Terms
(from Saunders' Pocket Essentials of Psychiatry)
Covers the basic terms most commonly used in psychiatry. The glossary is based primarily on Saunders' Pocket Essentials of Psychiatry. For a much more extensive glossary, see John Abess's Glossary of Psychiatric Terms (above).

Glossary of Sexuality Terms
(British Columbia Centre for Disease Control) (Click under "Glossary")
Useful glossary covering all sorts of terms related to sex, sexuality, sexual health, and sexually transmitted diseases.

Glossary of Symptoms and Mental Illnesses Affecting Teenagers
(American Academy of Child and Adolescent Psychiatry)
Good glossary of psychiatric terms related to teenagers.

Glossary of Terms for the Experimental Analysis of Behavior
(by Brittan Barker, Joy Kreider, Jessie Peissig, Greta Sokoloff, Maura Stansfield,
hosted on site of Edward Wasserman, University of Iowa) or
About 70 terms related to behaviorism, conditioning, learning, etc. Use in conjunction with the Glossary of Behaviorism Terms ("Glossary '57").

Glossary of Terms in Neuropsychology, Medical Psychology, & General Psychology
(Jacob L. Driesen, PhD)
Extensive glossary of terms used in neuropsychology, medical psychology, and psychology more generally. Find the glossary from the pull-down menu on the front page.

Google Definitions
In the search box, type in "define:" followed by any psychological or psychiatric word or phrase to receive immediate definitions from multiple websites. For instance, type in "define:psychosis" and receive brief definitions from 12 different websites.

Gray's Anatomy ( Edition)
This classic work from 1918 is the authority on anatomy. Features 13,000 detailed entries, with almost 1,250 illustrations (many in colour).

HyperStat Online Glossary of Statistical Terms
(David M. Lane, Rice University)
An excellent, comprehensive glossary of statistical terms.

Internet Mental Health Glossary
(Phillip W. Long, MD) (Click "Glossary" at top of screen)
Extensive glossary featuring very simple, brief definitions of psychiatric terms.

MedTerms Medical Dictionary
Definitions of terms and excellent detailed articles relating to psychiatry and mental health. Great for looking up brain anatomy terms. When you enter a term, you'll get a bunch of advertising on the top of the screen. Just scroll down past them to see your results.

Merck Manual of Diagnosis and Therapy, Seventeenth Edition
This is the online version of one of the most frequently consulted textbooks in medicine. Detailed full-text articles and charts cover the psychiatric disorders as well as all other areas of areas of medicine. If this address does not function, the manual may have been moved, in which case you should try to locate it at

Merck Manual of Medical Information, Second Home Edition
Provides easy-to-read, brief articles on various mental mental health disorders. Less detailed than the regular Merck Manual.

Merck Manual of Health & Aging
Helpful, easy-to-read articles and charts covering: confusion, delirium, dementia, nerve disorders, movement disorders, sleep, mental health disorders, and thyroid disorders.

Merck Manual of Geriatrics, Third Edition
Focuses on the medical problems of the elderly, including: psychiatric disorders, delirium and dementia, neurologic disorders (sleep, movement, and sleep disorders), and metabolic and endocrine disorders. These articles are more detailed than those in the Merck Manual of Health & Aging.

Paxil Glossary
Brief, simple glossary explaining some common medication-related terms you may come across.

Personality Glossary
(G. Scott Acton, Rochester Institute of Technology)
A growing glossary of terms related to personality psychology.

Prisoner's Dictionary
A very extensive dictionary of terms used by prisoners and prison officials. Great site.

PsyBox: The Web's Biggest Dictionary of Psychology (at least the biggest free glossary)
Provides clear, concise definitions for about 700 psychology terms. This is a pretty extensive dictionary; it even lists the terms dramaturgical theory, isomorphism, phenomenology, and thanatos! I use this with the AlleyDog's psychology glossary, which is just as extensive (but which doesn't cover as many technical and obscure terms as PsyBox) and with the much larger and more detailed Gleitman glossary (which is great, but may not stay free for too long).

Psychology/Basic Glossary
(Henry Gleitman, University of Pennsylvania;
Alan Fridlund, University of California, Santa Barbara; Daniel Reisberg, Reed College)
Perhaps the biggest online psychology glossary, covering about 1,150 terms. From the authors of the popular introductory textbook, Psychology. To view entries for different letters, just change the last part of the URL (eg, to see words beginning with P, type in Although the glossary covers basic, introductory terms, the definitions in this glossary are a bit more detailed than the ones in the other glossaries. I use this glossary along with PsyBox's dictionary and the AlleyDog's psychology glossary, which are not as large, but cover more obscure terms than the Gleitman. Note: I, J, X, Y, and Z seem to be missing.

Sex Dictionary: Sex Words Defined and Explained
The Internet's premier sex dictionary.

Sexuality Dictionary
(Sinclair Intimacy Institute)
Covers over 270 sexuality-related terms.

The Skeptic's Dictionary
(Robert T. Carroll)
"Featuring nearly 400 definitions, arguments, and essays on occult topics ranging from acupuncture to zombies, The Skeptic’s Dictionary is a lively, commonsense trove of detailed information on all things supernatural, paranormal, and pseudoscientific ... It covers such categories as alternative medicine; cryptozoology; extraterrestrials and UFOs; frauds and hoaxes; junk science; New Age energy; the paranormal, and the psychic. Also covered are dozens of topics in logic and perception and science and philosophy that help explain the appeal and popularity of occult beliefs, as well as guide the reader to think critically about them." Provides biased, but critical coverage of such psychological topics as: co-dependency; The Enneagram; EMDR; facilitated communication; hypnosis; IQ and race; Carl Jung, synchronicity, and the collective unconscious; lie detector; Mozart effect; multiple personality disorder; the Myers-Briggs Type Indicator; neurolinguistic programming; New Age therapies; parapsychology; penile plethysmograph; personology; phrenology; physiognomy; psychoanalysis; repressed memory therapy; Rorschach inkblot test; speed reading; subliminal advertising; testimonials; and the unconscious mind. Features extensive lists of articles and resources, especially on critical thinking (there are even 9 critical thinking mini-lessons). The dictionary is also available in print format.

Sleep Dictionary (Sleepnet)
An excellent dictionary of 400+ sleep-related terms.

Suicide and Suicide Prevention Glossary
(Suicide Prevention Resource Center)
Glossary of terms commonly used in the suicide and suicide prevention field. PDF version of glossary available.

Wikipedia Encyclopedia
The world's largest free and open-source general information encyclopedia (nearly 400,000 English-language entries) is a great place to look up all sorts of terms and issues relating to all areas of psychology, psychiatry, and mental health. (Because these articles are not peer-reviewed and can be edited by anyone, they should not be relied upon exclusively for authoritative information). I use this in conjunction with the Gale Encyclopedia of Psychology, the Gale Encyclopedia of Childhood and Adolescence, and


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