rumination

This term describes a cycle of repetitive thought that often leans toward the negative or the obsessive. While contemplation is generally purposeful and productive, rumination suggests a mental loop where the individual is stuck on a problem or a regret without reaching a resolution, mirroring the physical act of chewing the same food repeatedly.

In a biological sense, the word refers to the specific digestive mechanism of ungulates. This literal process of regurgitation and re-chewing provides the vivid imagery for the psychological meaning, linking the physical grinding of food to the mental grinding of an idea.