Gold standard
From ACT Wiki
1. Currencies - hard money - fiat currencies.
A monetary agreement under which national currencies were backed by gold, and gold was used for international payments.
Most countries abandoned the gold standard for their currencies during the 20th century.
Fiat currencies are the - almost universal - alternative.
2. Standard of excellence.
A gold standard is an example of something that is very good that is used as a measure of how good other things are.
Many providers say that their own offerings are the "gold standard" in their field.