주조 과정에서 발생한 결함이나 오류가 있는 동전
A coin that has a minting error or physical defect, often valued by collectors.
예문:
"The collector was thrilled to find a rare fido with a double-struck image."
"While most fidos are discarded at the mint, some manage to enter circulation."
"He specializes in identifying fidos that other hobbyists might overlook."