What's this UI pattern called?

Question

I\'m trying to figure out what this sort of thing is called, and eventually how I can create one in a web browser. It looks like this (screenshot of the first app that came

Answer 1

I've always thought it was called an accumulator, but I had a very hard time finding anything to support that on Google. Here's a mention of it in an obscure philosophy graduate thesis about UI usability.

Figure 4-1 shows an example of a reorientation rule applied to an accumulator widget (i.e. a component transferring items from the left list of possible values to the right list of accumulated selected items).

And another mention in some student projects from 1998.