The process takes a plaintext message (c) and uses a algorithm and a private key to encode it into ciphertext (d), which is then decoded by the recipient using a public key.
What definition of encryption do you use that doesn't fit this process?
It does not encode it into a ciphertext at all. Did you read the article? You do not get back the message, actually there is no way to get back to the message with this signature.
In this case, the hash is the message being encrypted. It's the (c), as I indicated in my previous post. The text being signed is not encrypted, but the signature still involves encryption.
What definition of encryption do you use that doesn't fit this process?