“Romaji” in Wikipedia literally redirects to “Romanization of Japanese” which says “This method of writing is sometimes referred to in Japanese as rōmaji”. It sounds like your effort might be better spent fixing those problems in Wikipedia before continuing with the rest of the discussion here.

> "Romaji" does not (in English) mean "romanisation"

> This method of writing is sometimes referred to in Japanese as rōmaji

See how there's not actually a contradiction there?

Can you just explain what you’re trying to say. I genuinely don’t understand your point. What is my mistake?

You're saying "romaji" when you mean "romanisation". Yes in Japanese it's called ヘボン式ローマ字, but when people use "romaji" as a loanword in English it's generally understood to mean the written characters, the result of romanisation, not the process of romanisation (and certainly not "Hepburn romanisation specifically as distinct from other romanisation systems", but you've already non-apologised for that).

I don’t know what post you’re referring to. I understand romaji is the character set.

If you’re nitpicking on this sentence:

> I thought it’s acceptable to refer to Hepburn as just “romaji”

I’ll expand it:

> I thought it’s acceptable to refer to Hepburn [-flavored romaji] as just “romaji”

I think it’s clear by context what I was saying.