Narratology denotes both the theory and the study of narrative
A narrative is a constructive format that describes a sequence of non-fictional or fictional events. The word derives from the Latin verb narrare, "to recount", and is related to the adjective gnarus, "knowing" or "skilled"...

 and narrative structure
Narrative structure
Narrative structure is generally described as the structural framework that underlies the order and manner in which a narrative is presented to a reader, listener, or viewer....

 and the ways that these affect our perception. While in principle the word may refer to any systematic study of narrative, in practice its usage is rather more restricted. It is an anglicisation of French narratologie, coined by Tzvetan Todorov
Tzvetan Todorov
Tzvetan Todorov is a Franco-Bulgarian philosopher. He has lived in France since 1963 with his wife Nancy Huston and their two children, writing books and essays about literary theory, thought history and culture theory....

 (Grammaire du Décaméron, 1969). Narratology is applied retrospectively as well to work predating its coinage.