The word "mewing" has a couple of meanings, depending on the context. Primarily, it refers to the act of a cat or kitten making a high-pitched sound, which is often a request for attention or food. In a more specialized context, "mewing" can also refer to a technique of tongue posture alignment, where the tongue is placed against the roof of the mouth, believed by some to enhance facial structure over time.
Purring
For the tongue posture meaning:
Quietness
For the tongue posture meaning:
The term "mew" has its origins from the Middle English word "mewen," which is a variant of the Old English "mēowan," meaning to make a sound like a cat. The word "mew" itself is believed to be imitative of the sound made by cats.