There's no standard. "key" and "keyfile" are the most common, but they're not the only option. It can also be referred to as a "password file", since there's really not much difference between the concept of a password/passphrase and a key. A password is basically just a key you can remember, and hence tends to be shorter and legible. That's why e.g. from cryptsetup-open(8):

> --key-file Read the passphrase from the file.

They're synonyms to a degree.

Re: "passkey". You can search github:

> The password key file can then be used with the --passkey option. It provides the same security level as using the --passfile option but helps in setting up and using separate key files for different wallets.

> parser.add_argument('--passkey', help='YOUR_PASSWORD')

On

> Google Trends also indicates nobody was caring about "passkey" before 2022.

I think how this tends to happen is you have a term in a population and a larger population outside of it sees it in a very specific context and tightly ties the term to that very specific context. With the "masa" thing, when you're working with dough you don't tend to always specify "get me the wheat dough". You just leave the type implicit. Sufficient English-speakers must have heard "masa" in Mexico or something, where most dough tends to be made of corn and assumed that the term "masa" must only be usable in the context of "corn".