Goth is a modern popular subculture that first appeared in the punk era in the 1970s. It is often associated with a particular style of music and a "uniform" that goes with it, typically all black with velvet and leather being two primary materials worn.
The term is often more easily defined by what it is not, rather than what it is. This, ironically enough, goes hand-in-black velvet glove with its nihilistic associations. The word is variously capitalized. Its uses are manifold; to describe something as 'goth' is to confer praise or derision, notoriety or obscurity, worth or dismissal, depending on one's opinion of the matter. Goth is a term tied closely to identity and personal expression, and as such leads to debate.
Some claim that goth is defined by androgyny, black clothes, black hair dye, death, darkness, depression, heavy makeup, horror (inspired by fiction and film), Nihilism, sensuality, silver jewellery or any number of other things. Others protest that these categories are stereotypical and generally cause more harm than good.
The word goth, as it relates to the modern subculture, is a neologism laid claim to by a number of famous figures associated with the goth movement  (http://www.scathe.demon.co.uk/histgoth/name.htm).
The meaning and implications of the term have naturally evolved through the years, though it seems to have been used, at the time, to describe the new 1980s post-punk bands; bands which were close to the spirit of punk, but with a more despairing, introverted form of anger.
It is also debatable as to whether goth is really a subculture, since such a thing is characterised by unified beliefs and outlook, whereas goth is characterised by divergent beliefs and outlook. A large number of terms developed to describe goth types (e.g. Perkygoth[?], Mopeygoth[?], Visigoth). Some say there have been many goth subcultures, throughout the West because the goth movement's beginnings can be traced to various countries and thus various cultures. In referring to goth as a whole it is easier to call it a movement, driven by gothic fashion and gothic rock, its members exhibiting a general taste for a dark, supernatural aesthetic.
Goth is widely proposed to have begun c. 1976 in Britain as an off-shoot of the Punk movement with the formation of Easy Cure (now simply The Cure) and Siouxsie and the Banshees with other bands such as Bauhaus, Sex Gang Children[?] and Killing Joke[?] following closely afterwards; but there are others that claim it began in the 1960s with The Velvet Underground. Alice Cooper and Black Sabbath are also worth acknowledging, since despite rarely being considered core components of goth music, they were key influences in the darker trend music began to and has continued to take up to the present day.
Others that say the seeds were sown in the mid-19th century with the Gothic Revival[?] and the morbid outlook of the Victorians (partly owing to the state of national mourning which developed in response to Prince Albert's death, and partly to the Victoriansí general obsession with Christian funeral practices).
Others claim that goth had its beginnings in the gothic novel, the first of which is commonly agreed to have been Horace Walpole's The Castle of Otranto[?] (1764), or perhaps even earlier with the medieval gothic period[?].
The goth movement has certainly been going for a long time, and shows no sign of stopping. This owes much to its evolution, despite its dogged resistance to change and pervasive desire amongst its members to tie goth down to some core ideal or value-set.
In the UK, the names most often mentioned would be The Cure, Siouxsie and the Banshees, Joy Division, Bauhaus, Specimen[?], and Alien Sex Fiend[?]. Each of these bands had much in common with the punk movement, though any similarity with punk was owed to the fact that that was the scene from which they were emerging, and were attempting (whether consciously or unconsciously) to leave behind. What is most notable about the core early '80s post punk bands is that, typical to their punk roots, they had a general distaste for labels, presumably seeing such things as anathema to creative expression  (http://www.gothics.org/subculture/articles/undead.php). In recent years, the tendency has swung almost entirely the other way, with many bands being quick to label themselves as goth.
From the late seventies onward, the Death Rock movement in Los Angeles, California was on the rise, with such bands as Gun Club[?], 45 Grave[?], Christian Death, Black Flag, and Penis Flytrap[?] at the forefront. Nivek Ogre[?]'s Skinny Puppy (formed c. 1982) were also doing their "thing", quite apart from the Death Rock scene. Whilst all of groups began as quite distinct from goth, they soon began to be equated with it, and are now recognised as strong early influences.
Goth was as much a European phenomenon as it was British or American. At the same time that The Cure and Christian Death were forming in those countries, in Germany (home to the largest modern gothic festival, the yearly Wave Gotik Treffen[?] in Leipzig) were such dark bands as Xmal Deutschland[?], Die Krupps[?], and Der Mussolini[?]. Belgium gave rise to Electronic Body Music (EBM) with influence from bands such as Kraftwerk and Front 242. Meanwhile, Amsterdam had Clan of Xymox[?].
Throughout the '80s, there was much cross-pollination between the European goth subcultures, the Death Rock movement, and the New Romantic (New Wave) movement. The rise in popularity of rock music in the mid-eighties, was mirrored by the rise of gothic rock, most notably in the form of the seminal goth rock[?] bands, The Sisters of Mercy, Fields of the Nephilim and The Mission.
The nineties saw the development of goth music in a more electronic-industrial direction, with bands such as Nine Inch Nails and Project Pitchfork[?] bringing a more processed edge to the goth music style. The largely German phenomenon of Darkwave[?] also evolved, with Das Ich[?] at the forefront.
With the arrival of Marilyn Manson (formerly Marilyn Manson and the Spooky Kids) the goth movement has became almost mainstream in popularity and has brought the "goth-not goth" debate to a head. This is perhaps most chiefly illustrated by the Columbine High Massacre, where the goth movement was blamed as being the corrupting influence behind the killings. This claim was based on the Trench Coat Mafia[?]'s tendency to wear makeup and dark clothing.
Many balk at the claim that Mansonites[?] are goths. Indeed to say as much is to commit heresy in many gothic circles. Spooky Kids[?] (as fans of the band have also been dubbed) are just not goth, along with McDonald's and brown corduroy[?] trousers. Others say that with many Mansonites consistently identifying themselves as goths, they speak for the movement, however much some may wish to deny them a place.