The terms "trade mark" and "brand" are often used interchangeably. Both can refer to a sign which distinguishes the goods (or services) of one trader from those of another. The sign could be, for example, a word or phrase, logo, picture, shape, sound, jingle or smell. The main function of a trade mark is to enable customers to recognise the goods or services as originating from a particular trader. Trade marks can be registered nationally or EU-wide. A registered trade mark is infringed if it is used without the consent of the owner, so the owner of the mark has a monopoly over the its use for the goods and/or services for which it is registered. This monopoly can be maintained indefinitely.