Wiktionary
tremissis
n. A coin of late Ancient Rome, worth one third of a solidus.
Wikipedia
Tremissis
Tremissis was a currency of the Late Ancient Rome, equal to one-third of a solidus. Tremissis coins were continued to be minted by descendants of the Roman Empire, such as Anglo-Saxon Britain or the Eastern Roman Empire.
Usage examples of "tremissis".
In the same mood he produces out of his desk a coin from the Dark Ages, a Merovingian gold Tremissis struck in Lyons about 675 A.