Pussy(cat) vs cat

What is the difference between a pussy or pussycat and just cat?

According to some soft sources, such as this yahoo answers question the term pussycat is a female cat, complementing the tom cat which is a male cat.

However, I can't find any dictionary that backs these claims, and some other sources even counter the claim as such, saying pussy(cat) is just the same as a cat. A tom cat however seems to be undisputed a male cat.

Multiple dictionaries list pussy(cat) as just plain "cat". Wikipedia mentions pussycat as a "pet domestic cat", but doesn't state any source for that.

Does anyone know the difference between pussy, pussycat, puss and cat?

Pussy[cat] is just an informal name for a cat.

pussycat 1: CAT

Merriam-Webster

It is a diminutive of "puss" (a much older word than I thought):

puss (n.1) "cat," 1520s, but probably much older than the record, perhaps imitative of the hissing sound commonly used to get a cat's attention. A conventional name for a cat in Germanic languages and as far off as Afghanistan; it is the root of the principal word for "cat" in Rumanian (pisica) and secondary words in Lithuanian (puž, word used for calling a cat), Low German (puus), Swedish dialect katte-pus, etc.

Online Etymology Dictionary

There is no specific word for a female cat but breeders use queen.

A.

Well, you know cat, obviously. Per the first sense in the OED,

A well-known carnivorous quadruped (Felis domesticus) which has long been domesticated, being kept to destroy mice, and as a house pet.

It has an uncertain origin somewhere in Europe before the 1st century AD and shows up in Greek, Latin, and Old English. In the past, it could specifically indicate the male cat but that's gone by the wayside. It's worth mentioning that it can include the big cats who fill out the rest of the genus Felis.

Puss (and earlier attested puss-cat)

A conventional proper or pet name for a cat, frequently (sometimes reduplicated) used as a call to attract its attention.

seem to have spread through the Germanic languages as an onomatopoeic pet name equivalent to what we'd now write as something like psst.

Pussy, the basic English diminutive for “puss,” shows up a century earlier as a way to refer to cat-like girls and girl-like men before being used

nursery and colloquial. A cat. Frequently used as a proper or pet name.

B.

There are loads of associations with the words, not all of which overlap. It's somewhat natural that people might assume “pussy” is a term for a female cat, given its affectionate diminutive nature and its (now much more common) use for female anatomy.

Really, though, the main difference is that “puss” and “pussy” are more childish, affectionate, and diminutive and more likely to be used as an unironic name or pet name.

The actual terms for a male cat listed by the OED are “he-cat,” “gib-cat,” “boar-cat,” and “ram-cat,” apart from the now more common tom or tomcat. For females, you've got “she-cat” and “doe-cat,” although Mr Random above says “queen” sees more use now.