A banknoteA banknote (or ‘bill’ as it is often referred to in the US) is a type of negotiable promissory note, issued by a bank or other licensed authority, payable to the bearer on demand. More security feature incorporated randomly during the manufacture of the paperSee Banknote paper. More. The fibres can be made of silk, plastic or metal, and may be visible, invisible, or fluorescent under UVAbbreviation for ultraviolet. More light.