"de facto"

de facto from Merriam-Webster

"사실상" when translated in Korean

<Examples>
English is de facto the universal language.
He is de facto the leader of our group.

*de facto standard: 사실상 표준
De facto standards are those which have been accepted as the best standard for their purpose. They have evolved to be accepted because of wide public support and market forces. This is often because they have a proven track record for efficiency and reliability. (from bbc.com)

ex. IBM when making a PC, Microsoft Window when making a computer OS