For decades, communication networks have been made up of servers, each known as a "node" in the overall network. Along comes AI with its neural network architecture comprising a matrix of mathematical nodes known as "neurons." See
neural network.
AI nodes are not physical hardware or software. They are abstract computations that are mapped onto the GPU hardware, which uses data from memory.
Recipe/Cooking Analogy
An interesting analogy for a neural network node is that it is a "step in a recipe" that uses "ingredients" stored in memory while the GPU does the "cooking." See
AI network and
server node.