The palaeencephalon is an important part of the brain associated with olfactory and emotional processes. However, it can be challenging to incorporate such a technical term into everyday language. Hence, it is helpful to be familiar with some synonyms that can be used in its place, including the primitive brain, limbic system, and reptilian brain. The primitive brain refers to the most ancient and fundamental part of the central nervous system, and the limbic system pertains to a network of structures that modulate emotional responses. Meanwhile, the reptilian brain denotes the basal brainstem and cerebellum, responsible for instinctual behaviors. Using these synonym options can help simplify complex discussions about the palaeencephalon and its role in brain function.