The sign function concerns the independence of the sign in relation to culture.

The sign function refers to the role played by the sign in creating a code.

The sign function is the cultural use of a sign - for example, using a cross to affirm that one is Christian.

The sign function is the function that signs play in communication.

The sign function is the function that makes the code work inside the sign and in the process of signification, linking the signifier to the signified.