If you're wondering what that meow means, it's helpful to listen to examples of cat sounds and compare. It's fascinating to hear the variations within a kitty's regular meows that can convey a broad array of complex desires and emotions.
Common Cat Sounds
Cats will vocalize their contentment, hostility, and inquiries through mostly different sounds. A 1978 study in Developmental Psychobiology reported that these vocalizations are specific to different circumstances. In other words, similar to how humans may have a different tone of voice to convey annoyance, surprise or happiness, cats can vocalize their 'feelings' in much the same way through the different sounds that they make.
Murmurs and Purring
Most people associate purring with petting. It is a common scenario for a cat to curl up on its owner's lap and purr during a quality petting. In such cases, purring does indicate contentment. Though the precise mechanism of purring is still somewhat of a mystery, scientists do know that purring is a combination of both the larynx muscle activity and the feline's vocal cords.
A classic example of purring can be seen in this video:
Purring is not always a sign of satisfaction and relaxation. A less commonly known fact is that cats will purr when they are stressed, frightened or in pain. Cats may also purr when they are nursing kittens or rubbing against the leg of a familiar friend.
The Standard Meow
Cats almost always meow as a direct means of seeking attention. Very frequently a cat will meow to indicate a need such as food, water, or a cherished activity. The pitch of a cat's meow varies from cat to cat. It can be high, low, very guttural or almost chirpy. This has little to do with the breed of cat and is entirely individualized from cat to cat, though kittens will often display a higher pitch than their mature counterparts.
The expectant meow of a kitten clamouring for food can be seen in the following video:
Howls and Growls
The stereotypical caterwaul and low visceral growl are not typically indications of hostility. Instead, these types of sounds demonstrate sexual desire in cats; females in heat and males who are calling for partnership often make these types of sounds. Such howls can be extremely loud and will also be heard during mating activity.
A standard heat-related howl can be heard in this video:
The Hostile Hiss
Hissing is almost always a sign of hostility. Though some cats will hiss when playing aggressively, this sound is typically associated with territorial urges and aggression. You should never touch or even approach a hissing cat, as this may signal a feline attack.
Hissing can be accompanied by hostile growling, as indicated in this video:
Cats who become extremely aggressive during mating or caterwauling may also hiss as a means of outing this aggression. It is also unwise to approach a cat who is experiencing this level of sexual aggression.
Biology of Cat Sounds
Small cats differ from large cats such as lions and tigers in the type of vocalizations they emit. As Animal Planet explains, the rigid structure of their voice box and the smaller chest cavity limits the domestic cat's range, but not its ability to use sounds for communication.
Vocalizations are determined by the physical structure of a cat, as well as the action of the respiratory system muscles and the acts of inhaling or exhaling. For example, cats meow when exhaling and will purr when both inhaling and exhaling, and this gives each vocalization its own unique sound.
Most cat owners are very well-acquainted with their pet's repertoire of sounds. A cat's ability to communicate the complexities of its existence vocally is a part of what makes owning a feline so fulfilling.