"Permission" means giving someone the approval or the right to do something. It is when someone allows or gives their consent for another person to do a specific action or take part in something. Full definition
To be clear, I did have explicit from permission from the photographer to use the photograph. (drkellyflanagan.com)
Some may require you to contact author for permission of use of the photo. (hubpages.com)
They could start sending and accepting bitcoin immediately with just their mobile phones, with no upfront costs, and without having to ask for permission from anyone. (coindesk.com)