The official name is actually
Node. Originally it was designed for use as a web application, but the author realized it could be used for more general purposes and renamed it to node.
Here is a quote from the author that may help explain the name:
Node is a single-threaded, single-process system which enforces shared-nothing design with OS process boundaries. It has rather good libraries for networking. I believe this to be a basis for designing very large distributed programs. The “nodes” need to be organized: given a communication protocol, told how to connect to each other. In the next couple months we are working on libraries for Node that allow these networks.