Definition - What does Gorilla Arm mean?
“Gorilla arm” is when someone who is using a vertical or standing touchscreen experiences fatigue or their arm starts to hurt, because of the awkward and not very ergonomic positioning that is required. It is called "gorilla arm" because of the similarity to the way a gorilla or other primate might interact with these vertical screens. Understanding gorilla arm and its use in the context of ergonomics reveals a lot of design elements that have driven new consumer products like tablets, two-in-one laptops, and other kinds of new touchscreen devices.
Gorilla arm is also known as gorilla arm syndrome.
Techopedia explains Gorilla Arm
Gorilla arm is what happens when the user interacts with a vertical touchscreen for a long period of time. The arm becomes tired, and it becomes more difficult to interact with the interface. One excellent example is the use of a floorstanding kiosk, the kind you might find in an airport library. Short-term use is relatively easy for most users — but as time goes on, the burden of raising the arm and making selections causes a certain kind of fatigue, since the arm is not physically supported in any way.
It might seem like a small detail, but the gorilla arm phenomenon has driven specific design elements in the most popular user devices on the market. For example, Apple does not include unsupported touchscreen technology for its devices because of user research on gorilla arm. So this term actually has a lot to do with how people physically interact with others on the Internet, or over other networks.