According to the Budapest Open Access Initiative (BOAI) of 2002, Open Access (OA) is the practice of making scientific literature freely accessible on the Web: the content of this literature can be read, downloaded, copied, distributed, printed etc. and the author should be credited for it. By making their work available in Open Access, authors allow the content to be used under an open license.
Source: Rafabollas, CC BY-SA 4.0, via Wikimedia Commons
