monometallism
noun
mono·met·al·lism ˌmä-nō-ˈme-tᵊl-ˌi-zəm 
: the adoption of one metal only in a currency
monometallist
ˌmä-nō-ˈme-tᵊl-ist
noun 
Word History
Etymology
International Scientific Vocabulary mon- + -metallism (as in bimetallism)
First Known Use
1878, in the meaning defined above