Symbolic usage is the use of a deictic expression in such a way that its interpretation depends only on general knowledge of the extralinguistic situation, rather than on physical (visual, and so forth) monitoring of it.
Levinson, Stephen C. 1983.Pragmatics. Cambridge, England: Cambridge University.
Fillmore, Charles J. 1975.Santa Cruz lectures on deixis: 1971. Bloomington, IN: Indiana University Linguistics Club.