Comment by QuantumNomad_

For anyone else wondering what the definition in Budapest Open Access Initiative is:

> By “open access” to this literature, we mean its free availability on the public internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles, crawl them for indexing, pass them as data to software, or use them for any other lawful purpose, without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself

https://www.budapestopenaccessinitiative.org/read/