The terms signifier and signified are used with reference to a sign, where a sign is any thing in the world that produces meaning for someone sensing it. A signifier is defined as the sensory impression that the sign gives us, whereas the signified is the abstract concept that a sign evokes.

Tony Thwaites further argues in 'Tools for Cultural Studies, an introduction' that a signifier is more accurately defined as the object that is perceived when all circumstances irrelevant to the understanding of the sign are removed.

For example, if the word 'Coca-cola' were taken to be a sign, irrelevant circumstances would include the accent in which the word was spoken, or the sort of text that it was written in. In the English language, it is understood that a certain combination of sounds or letters can be understood as the word 'Coca-cola', which constitutes the mental concept of a signifier.

To continue the example, for each individual that perceives the signifier 'Coca-cola', a mental concept arises which is directly caused by the signifier. An individual has a certain set of concepts of what constitutes 'Coca-cola'. These concepts have come to be associated with the original signifier through the individual's past experiences and thoughts. Over time, a link is built up so that when the signifier 'Coca-cola' arises, the signified concepts automatically arise.

According to Merriam-Webster's Collegiate Dictionary, arbitrary means "depending on individual discretion". We can consider the link between the signifier and the signified as dependant upon individual discretion because it is personally and socially constructed, and not absolutely defined. The signifier 'Coca-cola' can have many different signified meanings depending on the past experiences of an individual as well as societal norms.

For a simple example, one person might associate 'Coca-cola' in their mind with mental concepts comprising a delicious taste, social acceptance, a beverage and a slight caffeine-induced bodily stimulation. Another person might construct 'Coca-cola' with images of conformity, excessive marketing, corporate machinations and globalisation of culture.

Neither meaning is any less valid; they are simply different. Similarly, many signifiers can be associated with any signified meaning (for example, the signifier 'Microsoft' can also mean corporate machinations). It can be demonstrated that signs do not have single meanings, but many, thus they are dependant upon the senser.

However, it is feasible to argue that some signs are only somewhat arbitrary. Given the assumption of an English speaking society, it is not difficult to argue that the signifier 'yes' will universally be recognised as a function word to express assent or agreement. This occurs because in English speaking societies, individuals are very strongly socialised from birth to construct 'yes' in this way. While this not make the association natural, it can be argued that it is somewhat less than arbitrary.