The Gothic begins with later-eighteenth-century writers’ turn to the past.
In the context of the Romantic period, the Gothic is, then, a type of imitation medievalism.
When it was launched in the later eighteenth century, The Gothic featured accounts of terrifying experiences:
In ancient castles — experiences connected with subterranean dungeons, secret passageways, flickering lamps, screams, moans, bloody hands, ghosts, graveyards, and the rest.
By extension, it came to designate the macabre, mysterious, fantastic, supernatural, and, again, the terrifying, especially the pleasurably terrifying, in literature more generally.
Closer to the present, one sees the Gothic pervading Victorian literature (for example, in the novels of Dickens and the Brontës), American fiction (from Poe and Hawthorne through Faulkner), and of course the films, television, and videos of our own (in this respect, not-so-modern) culture.
Horace Walpole was it’s chief initiator, publishing The Castle of Otranto (1764), a short novel in which the ingredients are a haunted castle, a Byronic villain (before Byron’s time — and the villain’s name is Manfred!), mysterious deaths, supernatural happenings, a moaning ancestral portrait, a damsel in distress.
The best-selling author of the genre (Ann Radcliffe), the author of its most enduring novel (Mary Shelley), and the author of its most effective send up (Jane Austen) were all women.