Backend is a general word, not limited to client-server or the web. You can have a rendering backend with various configurable choices, like in Matplotlib (http

Backend is a general word, not limited to client-server or the web. You can have a rendering backend with various configurable choices, like in Matplotlib (https://matplotlib.org/stable/users/explain/figure/backends.html https://matplotlib.org/stable/users/explain/figure/backends....), or the deep learning library Keras has a choice between PyTorch, JAX and TensorFlow backends.