The ware is generally characterized by four criteria: manufacturing technique, function, typology or even dating, although exceptions are not uncommon. Its name is conventional.
The manufacturing technique is mainly defined by the assembly, finishing (smoothing, engobing, etc.) and firing technique (mode A, B and C, i.e. reduced ou oxydised). The functional criterion fundamentally distinguishes pottery for food consumption, preparation and serving, cooking, storage and transport, as well as all non-food terracotta elements. Typology is understood in the sense that a ware has one or more typologies. Dating makes it possible to distinguish wares that are similar in technique, function and repertoire, but are involved in different phenomena.
For example, turned low open shapes with a slip on the inside and fired in mode A are classified according to function and type, in terra rubra (TR) or in Pompeian red (RP). Terra nigra (TN) and dark regional fine pottery (FR), with a similar technique and repertoire, are distinguished by the period of production and use.