A fjord is a long, narrow, deep inlet of the sea between high cliffs or steep slopes, created by the submergence of a glaciated valley. Fjords are significant features in the study of glacial geomorphology, providing insights into past glacial activity, sea level changes, and the interaction between glaciers and coastal environments.
Reference: Syvitski, J. P. M., & Shaw, J. (1995). Sedimentology and Geomorphology of Fjords. Elsevier.