I'm writing up about different model architectures used in NLP, namely encoder-only models, encoder-decoder-only models, and have come across what seems to be a naming inconsistency. For decoder-only models it seems that they can be referred to as autoregressive models since they autoregressively predict the next token and encoder-decoder models can be referred to as sequence-to-sequence since they map a sequence of tokens to a different sequence of tokens.
However, I found various sources conflicting each other as to what an autoencoder is. While many sources claim that encoder-only models are autoencoders, others also refer to encoder-decoder models as being autoencoders.