What is what does purr mean?

Purring is a low continuous vibrating sound that cats make when they are happy, relaxed or content. It is produced by the contraction of muscles around the larynx and the diaphragm. It can also be a self-soothing technique for cats when they are feeling stressed or anxious. Purring can also be a form of communication between cats and between cats and humans. It can indicate affection, gratitude, and a desire for attention or food.