Glossary: Shrink

I thought I knew what a shrink was, but a recent misunderstanding on Twitter proved me wrong: A dictionary search shows that this word can also be used to describe psychiatrists only, and not clinical psychologists:

https://www.google.no/search?client=opera&q=shrink+definition&sourceid=opera&ie=utf-8&oe=utf-8&channel=suggest

a psychiatrist.

http://www.urbandictionary.com/define.php?term=shrink

a psychiatrist or mental doctor

http://www.merriam-webster.com/dictionary/shrink

[short for headshrinker] :  a clinical psychiatrist or psychologist

http://dictionary.reference.com/browse/shrink

Also, shrinker.  Also called head shrinker.  Slang.  a psychotherapist, psychiatrist, or psychoanalyst.

http://www.oxforddictionaries.com/definition/english/shrink

•  informal

A psychiatrist

https://answers.yahoo.com/question/index?qid=20081018042208AAvuhv9

Shrink", a slang term for a mental health professional such as a psychiatrist or psychologist (derived from the word "headshrinker")

http://dictionary.cambridge.org/dictionary/british/shrink_3

a psychiatrist or psychoanalyst