Meow

A meow (also spelled miaow) is a vocalization made by cats. Meows cover a wide range of sounds. Adult cats rarely direct meows at other cats; when an adult cat meows at a human, it's generally understood as a post-domestication carryover of kitten behavior — essentially a call for attention.

Before domestication, felines are thought to have communicated with one another primarily through scent and marking behaviors, which work better between cats than vocalizations do. As cats were domesticated, they picked up vocalizing as a way to communicate with humans. These vocalizations can indicate hunger, a desire to go outside, or simple greetings.

The mew

A mew is a high-pitched meow most often made by kittens. Kittens apparently use it to get their mother's attention. Adult cats may also mew when distressed or sad, or to signal submission.

A learned behavior

Meowing is fundamentally a learned behavior. Feral cats meow far less frequently than cats living with people. Over time, cats can learn to meow in response to human speech, producing a back-and-forth that resembles a conversation in everything but content.

Etymology

In American English, the spelling meow was first used in 1842. Earlier spellings included miaow, miau, and meaw, derived from the French miau. The earliest attestation of a cat's cry in Early Modern English, across any of these spellings, dates from the 1630s.