The following is a rather lengthy explanation of why these word were chosen:
Autonomous is most commonly used to describe the behavior of an individual or governing body as independent or self-governing. It is believed Jennifer Allen selected this term because of this common meaning. She saw the large variety of stimuli that trigger ASMR as it being “individualistic”, in the same way that we all enjoy food but we each have our individual preferences. She also selected this term for the “self-governing” meaning because it describes those individuals whom do not need any external stimuli to experience ASMR, their experience is “self-governing.”
Although autonomous is not widely used to describe biological pathways, there is a very similar word used in biology that has the same meaning because they share the same word origins. “Autonomic” is a term that describes nerve pathways that leave the brain and regulate the activity of your organs. Autonomic also means independent and self-governing because these biological processes work without you needing to think about them. When you want to pick up a pencil, that is not an autonomic signal because you have to think about it to make it happen. But when your heart rate speeds up or slows down that is considered autonomic because you do not need to think about it.
In time, I think research will show that there are some autonomic responses with ASMR. When people experience ASMR they probably have a lot of classic autonomic responses like decreased breathing rate, decreased heart rate, and increased digestive system activity. So the “autonomous” term in ASMR is an excellent descriptor for the variety of triggers, the ability of individuals to experience ASMR without any triggers, and the autonomic responses that occur in the body during ASMR.
She has shared that she chose the term meridian because it meant a period of high prosperity or success. It may be serendipity that meridian has other meanings that seem to also fit well with ASMR.
Another meaning of meridian is as a term from traditional Chinese medicine to describe the pathways of life-energy flow. Many people who experience ASMR would probably agree that they feel like some kind of tingly electric feeling is flowing throughout their body.
Another meaning of meridian is a line that runs between the North Pole and the South Pole.
If you combine together some of these meanings of meridian, you sorta have a very good description of the central nervous system, which carries electrical signals between the tops of our heads and the bottoms of our spinal cords. And the tingles from ASMR are probably mediated by neurotransmitters initiating impulses along our central nervous system.
I believe that Jennifer Allen also had a broader and important reason for coining the term “ASMR.” ASMR is a term that is more likely to be taken seriously and receive the attention of researchers and funding agencies, than terms like head orgasms and brain tingles.
asmruniversity.com/2014/08/03/scientist-view-term-autonomous-sensory-meridian-response/