Differing from a symbol or an allegory, a typology is a representation of an actual, historical reference. According to Christian exegesis, biblical typology deals with the parallels between actual, historical (usually OT) figures or events in salvation history and their later, analogous fulfillment. Often NT events and figures are typologically understood and interpreted according to an OT pattern (e.g., creation and the new creation, Adam and Christ, the exodus and NT concepts of salvation). On this basis typology became one of the four prevalent ways (together with the literal, the analogical and the spiritual) of interpreting Scripture in the Middle Ages.
*Stanley J. Grenz, David Guretzki &, Cherith Fee Nordling, Pocket Dictionary of Theological Terms (Downers Grove, IL: InterVarsity Press, 1999), p. 117