Origins of the term "Goth"
The name "goth" originally came from a Germanic tribe (ie the Goths). The Romans regarded them as barbaric and uncultured, much like the Vandals. "Gothic" was later applied to a style of medieval architecture by critics who regarded it as similarly barbaric and uncultured (something similar happened with the term "Vandal"). The term was later applied to a late 18th/early 19th century style of literature which had a fascination with death and the supernatural.
Exactly how "goth" became applied to the post-punk musical movement is unclear. The earliest use is likely to have been by Martin Hannett, Joy Division's producer (see below), in 1979. By late 1979 and early 1980, the term "gothic" seems to have been fairly common in music journalism to describe bands such as Joy Division and the Banshees. In 1981 Abbo used the term "gothic" to describe the emerging band movement. Then later, probably about 1982, Ian Astbury used the term "goths" to describe Sex Gang Children's fans. On the surface, there seems to be a clear progression here, with the term gothic/goth being used to describe first individual bands, then a movement of bands, then the followers of that movement.
However, it's not that simple. The term "goth" doesn't seem to have been commonly applied to the movement until 1984, several years after it had originally been used. In 1983, the most common term for what became the goth movement was "Positive Punk", or later "Posi-Punk", courtesy of Richard North in the NME.
Somehow, and probably sometime in late1983 or early 1984, the term seems to have been replaced by "goth".
What seems to have happened is that the term had been floating around, was occasionally used to describe bands, and eventually stuck. No individual person was solely responsible, but details of early significant usages are given below:
Joy Division
The first dateable use of the term "gothic" in relation to music was by Tony Wilson, who described Joy Division as gothic compared with the pop mainstream on a BBC TV programme, "Something Else" (15/9/79), when Tony Wilson and Steve Morris were interviewed. This is unlikely to be the earliest use of it, though.
In a Factory Records interview by Mary Hannon (source unknown, date post-UP, pre-Closer), there is the following passage:
"One clue to JD lies in their album's title. Another is the description given by Martin Hannett, who calls them 'dancing music, with gothic overtones'. Unintentionally, Bernard Albrecht gave an excellent description of 'gothic' in our interview, when describing his favourite film 'Nosferatu'. 'The atmosphere is really evil, but you feel comfortable inside it'."
The article goes on to describe JD as "20th century gothic".
Unfortunately I have neither date nor source
In any case, it presumably pre-dates the following band reviews:
[Review by Penny Kiley, Liverpool, Buzzcocks support tour, gig 2/10/79]
"'Gothic' has become a somewhat overworked definition of the genre, but the effect of Joy Division is the same as (to take an obvious example) that of the Banshees."
[Review by "Des Moines"(?), Leeds, Buzzcocks support tour, gig 3/10/79]
"Curtis may project like an ambidextrous baarman purging his physical hang-ups, but the 'gothic dance music' he orchestrates..."
[Review by Chris Bohn, University of London Union, gig 8/2/80]
"Joy Division are masters of this gothic gloom..."
As can be seen from the above, after the interview by Mary Hannon "Gothic" seems to have become a quite common term describing Joy Division and certain other groups. It's possible the Banshees may have also used the term independently to describe their new direction, but I don't know whether that would pre or post date the Mary Hannon interview.
In any event, I'd hazard a guess that Hannett's "gothic overtones" comment pre-dates Wilson's supposed comment, as there are only two and a half weeks between Wilson's comment and Penny Kiley's description of the term gothic as "overworked" (although two weeks can be a long time in journalism). Since Unknown Pleasures came out in May/June 79, I'd guess Hannett's comment can be loosely dated to summer 1979.
UK Decay
In an interview with Steve Keaton from Sounds in February 1981, Abbo from UK Decay inadvertently named the goth movement: "he said 'it's gonna be a movement' and we're going nah, we'll be gone in six months. He said you've got to get a name for it, it's not dance or alternative or New Pop or mod... and I remember saying 'we're into the whole Gothic thing'... and we sat there laughing about how we should have gargoyle shaped records and only play churches. Course he put it all in the interview.. for six months everything went quiet then when the album came out everyone was asking 'what's this Gothic thing you're into?' And it's a total joke!"
Ian Astbury/Andi Sex Gang/The NME
In an interview with Dave Thompson and Jo-Anne Green of Alternative Press magazine in November 1994, Ian Astbury, the vocalist in Southern Death Cult, laid claim to having invented the goth tag:
"The goth tag was a bit of a joke," insists Ian Astbury. "One of the groups coming up at the same time as us was Sex Gang Children, and Andi -- he used to dress like a Banshees fan, and I used to call him the Gothic Goblin because he was a little guy, and he's dark. He used to like Edith Piaf and this macabre music, and he lived in a building in Brixton called Visigoth Towers. So he was the little Gothic Goblin, and his followers were Goths. That's where goth came from."
And again in an article entitled "The Gloom Generation,"by Suzan Colon which appeared in the July 1997 edition of Details Magazine:
" For a lot of people who had been in it a few years before, punk no longer resembled what they had originally intended it to be. Goth gave them a chance to establish another platform that was specifically theirs. This new scene attracted the dispossessed, a lot of punks living on welfare, shoplifting. Many of them lived in Brixton in the early '80s because it was cheap. There was one band called Sex Gang Children who dressed in a very similar fashion to Bauhaus and Specimen. A load of us used to hang out with their singer, Andi SexGang. He lived on the top floor of an old Victorian house. We'd go up there for tea, and he'd be in a Chinese robe with black eye makeup on and his hair all done up, playing Edith Piaf albums with fifteen TVs turned on. We had this vision of him as Count Visigoth in his tower, holding court. At the time, Dave Dorrell heard us calling Andi "Count Visigoth" and his followers "goths," so that's what he called everyone in the scene."
This would be around 1983 (when both bands were "coming up") and thus post-dates both Hannett's and Abbo's use of the term "gothic", but is probably the first use of the term "goths" to describe devotees of a certain type of musical style.
Importantly, David Dorrell used to write for the NME...
Here's a further quote from the same article:
"PETE MURPHY: I know that Bauhaus presumably started what the critics coined the "gothic" genre in 1979 with "Bela Lugosi's Dead," but goth was a myth dreamt up by journalists sometime back in the '80s to describe Bauhaus, Joy Division, Iggy's vocal vibe on The Idiot, and so on. The music was often unaccomplished, but made up for it with a kind of transcendent quality.
DANIEL ASH: When we recorded "Bela Lugosi's Dead," Bauhaus had only been together for four weeks. We never called ourselves or our music: "goth." That was something that came a few years later from the press.
DAVID DORRELL: Oh, God, it all comes back! I won't even try and make claims that I wrote an article and called them goths or whether I cribbed that off one of my fellow goth journalists -- speed burns my memory. As a journalist, I noticed that the end of punk was starting to get darker. (John) Lydon was getting dark with Public Image Ltd. By committing suicide, Ian Curtis of Joy Division not only put an end to his own life and that of his band, but allowed a vacuum to occur into which all of these other bands scurried."
Depite Dorrell's memory lapse, it seems likely that Astbury was right and Dorrell picked up the tag from the description of Andi Sex Gang & co.
Siouxsie
At some point in her career, Siouxsie used "gothic" to describe the Banshees' new musical direction. I'm not sure when this was, but the most probable time would be around the release of "Juju"(June 1981), their most obviously gothic album (looking at Penny Kiley's review above it might have been earlier, around 79, but this is a little early to be talking about a new musical direction).