Guilder is the English translation of the Dutchgulden — from Old Dutch for 'golden'. The guilder originated as a gold coin (hence the name) but has been a common name for a silver or base metal coin for some centuries. The name has often been interchangeable with florin.
One-and-a-half guilder was called a daalder (see thaler); two-and-a-half guilder was called a rijksdaalder. The word daalder/thaler is the origin of dollar.
