Trademark distinctiveness is an important concept in the law governing trademarks and service marks. A trademark may be eligible for registration, or registrable, if it performs the essential trademark function, and has distinctive character. Registrability can be understood as a continuum, with "inherently distinctive" marks at one end, "generic" and "descriptive" marks with no distinctive character at the other end, and "suggestive" and "arbitrary" marks lying between these two points. "Descriptive" marks must acquire distinctiveness through secondary meaning - consumers have come to recognize the mark as a source indicator - to be protectable. "Generic" terms are used to refer to the product or service itself and cannot be used as trademarks.
In United States trademark law, Abercrombie & Fitch Co. v. Hunting World 537 F.2d 4 (2nd Cir. 1976) established the spectrum of trademark distinctiveness in the US, breaking trademarks into classes which are accorded differing degrees of protection. Courts often speak of marks falling along the following "spectrum of distinctiveness," also known within the US as the "Abercrombie classification" or "Abercrombie factors":
A fanciful / inherently distinctive trademark is prima facie registrable, and comprises an entirely invented or "fanciful" sign. For example, "Kodak" had no meaning before it was adopted and used as a trademark in relation to goods, whether photographic goods or otherwise. Invented marks are neologisms which will not previously have been found in any dictionary.
An arbitrary trademark is usually a common word which is used in a meaningless context (e.g. "Apple" for computers). Such marks consist of words or images which have some dictionary meaning before being adopted as trademarks, but which are used in connection with products or services unrelated to that dictionary meaning. Arbitrary marks are also immediately eligible for registration. Salty would be an arbitrary mark if it used in connection with e.g. telephones such as in Salty Telephones, as the term "salt" has no particular connection with such products.