Ground is a term proposed by Charles Sanders Peirce to define the meaning or meanings that something created to function as a sign vehicle has.
Not all of the characteristics of a sign vehicle are essential to its function. For example, a STOP road sign would bear the same meaning whether it is created of wood or metal. Still, its form – octagonal or triangular, and its color – whether it is painted in red or in blue are of crucial importance for people to read it correctly.
There are specific characteristics that are letting the STOP road sign actually function as a STOP sign. It is precisely those characteristics that are letting a sign function as itself what Peirce calls ground. That is so, as it is precisely these characteristics that are letting an object, unit or event function as a sign vehicle.
Some contemporary interpreters such as Thomas L. Short for example are building significant research around the idea that ground was replaced by the representative classification of sign functions – sign classification according to the relationship to their objects. Following the latter classification, some things are suitable to be sign vehicles as they resemble their objects (which makes them iconic signs). On the other hand, things could be suitable to be sign vehicles due to their current physical relation to their objects (which makes them an Indexical sign). And further others are eligible to be sign vehicles due to the relation they have with their objects, a relation, based on habits (which makes them Symbolic signs).
In this way, the classification of the sign vehicles in the categories of Indexical, Iconic, and Symbolic signs demonstrates the meaning in which something is suitable or created to represent (denote) its object.
Therefore, some authors believe, that this classification could be used to replace the generic idea of ground.
