“Semiology is defined as, ‘a science which studies the role of signs as partof social life… it [semiology] would investigate the nature of signs and the laws governing them'(CMS 101).” Ferdinand Saussure is generally regarded as the founder of this study. He argued that all signs were a combination of signifier and signified (CMS, 102). The signifier refers to the material form of a sign as perceived by the senses (CMS, 102). The signified is the idea evoked by the signifier.
The thing I find interesting about this process is that when we see certain signifiers we automatically think of the signified. In addition to this fact, if we didn’t have previous knowledge the signs wouldn’t make sense. For example, it is not naturally set in our minds to know that red means stop and green means go, but since we have been conditioned to think that way we understand the sign.