Semiotic Icon
A semiotic icon functions as a signifier for some idea or idea system because it physically resembles the signified, at least if interpreted by means of a rule-governed interpretive code that guarantees all rule-following readers will assign it the same value.
The Pietá (Christ and Madonna as a generic scene, in which the child signifies ideas associated with vulnerable divinity and the mother signifies ideas associated with nurturing adoration)
The American Flag (a piece of cloth composed of a coded pattern of stars and stripes which signify [in number] the original colonies and current states and [in color] loyalty and blood). Click here for Robert E. Bonner's "Star-Spangled Sentiment," a historical (non-Structuralist) study of the growth of the American flag cult.