Modern linguistics during the last hundred years has taken as its starting point in any discussion of meaning the conventional acceptance of the need for the relationship between word and object to be an indirect one mediated by a concept. Building on this assumption, de Saussure (1938) provides a rather more explicit model of the relationship in which the link is shown to be between the linguistic sign and the object. De Saussures model consists in seeing the linguistic sign itself as being composed of two indivisible elements, a signifier and its signified or the concept and the acoustic image which realizes it. An example of this may be the relationship between the word 'tree' and the actual tree perceived by the sense which is referred to by using the word.