In semiology, the basic unit of signification composed of signifier (which carries the meaning) and signified (which is the concept or thing signified). In written language, for example, the word "tree" is the signifier, the idea of the tree the signified; the whole sign is comprised of both elements. In cinema, the signified, the idea of tree, remains the same, but the signifier, the image (or even the sound) of the tree is much more complex. See semiology.