Final answer:
A wide, low-pitched gable surmounting a colonnade or a major division of a façade is called a pediment in classical architecture.
Step-by-step explanation:
The architectural term for a wide, low-pitched gable surmounting a colonnade or a major division of a façade is a pediment. This triangular space forming the gable is a characteristic feature of classical architecture, associated with Greek and Roman temples.
The pediment typically lies horizontally atop the columns, forming part of the entablature, and it is often decorated with sculptures or reliefs depicting mythological or historical scenes.
The terms provided in the question can be associated with various architectural features, but within the context of a classical façade, the pediment is the element that corresponds to the definition of a wide and low-pitched gable.