Gothic is really hard to define. Sometimes there's haunted castles and sometimes there's ruined manor houses. Sometimes there's explicit supernatural elements and sometimes there's not. Sometimes it's a male genre with blood and guts and violence and sometimes it's a female genre with psychological suspense and no blood in sight. What seems to be the defining element is that it is a genre about powerful emotions driving characters to extremes of behavior -- love, madness, murder, sacrifice, etc -- that take the readers (or viewers) out of the safe confines of the regular world and into a heightened reality where the audience can experience the catharsis of unfettered desires and the terror of suppressed ones. Let's look at some examples:
Jane Eyre is about a psychologically abused orphan who goes to live with a scary rich man. It's kind of like "Little Orphan Annie," but not. Eventually she finds out he has his crazy wife locked in the attic, but everything turns out okay after he gets deformed in a fire and she finds out she's rich and she really loves him anyway. There's nothing explicitly supernatural in it. Read it here. Hey, look! Magneto!
Wuthering Heights is about a trio of a**holes with poor impulse control who let their histrionics get the better of them and try to ruin the lives of everyone who is nice to them -- and their own children. There's nothing explicitly supernatural in this one either, though the biggest a**hole in the story has hallucinations (and humps a corpse). Read it here. Hey, look! Bane!
Frankenstein is an allegory for women's fear of childbirth. (Think about it.) There's certainly some science-fantasy in this one. Read it here. Hey, look! Henry V!
"Twin Peaks" is about a nice guy who goes to a remote backwater village and finds murderous goings-on and freaky psychological convolutions. There is plenty of the supernatural in this one. You can watch it on Netflix. Hey, look! Muad'dib!
"Army of Darkness" is NOT A GOTHIC! Yes, there's skeletons and demons. Yes, there's castles and swords. Yes, there's a lot of screaming. Yes, Ash lets his emotions get the better of him. But seriously, dudes, we all know this isn't a story with deep psychological roots (even if it is one of my favorite films). Gothic is about the deeper underpinnings, not hacking things to pieces with a chainsaw. You can watch it on YouTube. Hey, look! Sam Axe!
Maybe a way to describe the Gothic is "Kinda like Lovecraft, but with hope." Or maybe not. It's really hard to define, but you'll know it when you feel it (not when you see it) because "feeling" is what Gothic is all about.