Deixis and Indexicality
The terms deixis and indexicality are frequently used almost interchangeably, and both deal with essentially the same idea: contextually dependent references. However, the two terms have different histories and traditions. In the past, deixis was associated specifically with spatiotemporal reference whereas indexicality was used more broadly. More importantly, each is associated with a different field of study; deixis is associated with linguistics, while indexicality is associated with philosophy.
Read more about this topic: Deixis