Semiotics (or semiology) is a discipline derived from American logician, C. S. Pierce, and Ferdinand de Saussure, the French linguist.  Peircian semiotics, with its roots in philosophy, is concerned with the study of signs and considers sign systems to be much broader than language.  In semiotics, Pierce developed a logic-centered orientation grounded in empirical observation.  Saussurian semiology is rooted in a study of language and the two-part sign relationship between a signifier and its signified.  Although he admits that signs can be other than words, Saussure focused his attention on how meaning is created through words.  Semiotics (or semiology) has come to mean generally the study of any cultural product (e.g., a text) as a formal system of signs.

Pierce used the concept of a “sign” to clarify his thoughts and found that an important tool for mental work was another concept, that of a sign relationship between the sign and the signified.  Peirce’s system for analyzing signs includes iconic, indexical and symbolic categories of meaning, which provide a much richer field for visual analysis.  Symbols are arbitrary and meaning is agreed to through convention; icons and indexes are “motivated,” that is they are more likely to resemble their object in some way.  Peirce defines an icon as similar to its subject—a representation such as a drawing or photograph where likeness or resemblance is a determining characteristic.  An index is physically connected with its object as an indication that something exists or has occurred, such as a footprint means someone walked by or smoke means there is a fire.  See http://spot.colorado.edu/~moriarts/primelang.html. 

(Where tie in my notes re Barthes book on sign/signified?  Here or later?)