The back of the A 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 or A coin is a small, flat, round piece of metal alloy (or combination of metals) used primarily as legal tender. Issued by government, they are standardised in weight and composition and are produced at ‘mints’. More. See Obverse.