Is Wuthering Heights a symbol of Gothicism?

Wuthering Heights most certainly fits the bill as a classic example of gothic literature. Gothic literature is well known for its surreal blend of fiction and horror, with plot points relating to death and even a sense of melancholy romance. All of this can be found in abundance in the titular moorland farmhouse of Wuthering Heights. The moors constitute a type of landscape which has itself become widely associated with the gothic genre.
The initial narrator, Lockwood, visits his brooding and eccentric landlord, Heathcliff, on the moor, where ethereal imagery and bleak landscapes keep the reader firmly anchored to the gothic aesthetic. Soon, events from the past begin to reveal the horror and grief of the events surrounding Wuthering Heights and its inhabitants, creating a literary masterstroke in true gothic fashion.

Emily Brontë's Wuthering Heights is an example of the Gothic literary genre. Gothic literature, which flourished in the late 18th and 19th centuries, can be identified by a few key ingredients. Gothic fiction often combines elements of horror and the supernatural and sets them against a gloomy, foreboding setting. In many (but not all) cases, the plot heavily features characters in the throes of madness, obsession, and romance. Let's look at the setting of Wuthering Heights first:

Wuthering Heights is the name of Mr. Heathcliff’s dwelling. ‘Wuthering’ being a significant provincial adjective, descriptive of the atmospheric tumult to which its station is exposed in stormy weather. Pure, bracing ventilation they must have up there at all times, indeed: one may guess the power of the north wind blowing over the edge, by the excessive slant of a few stunted firs at the end of the house; and by a range of gaunt thorns all stretching their limbs one way, as if craving alms of the sun. Happily, the architect had foresight to build it strong: the narrow windows are deeply set in the wall, and the corners defended with large jutting stones.

In the very first chapter, Brontë establishes the moody setting of the Wuthering Heights estate against the moors. This desolate and tumultuous setting reflects the characters' moods and motivations.
Supernatural elements abound in Wuthering Heights. Ghosts and rumors of ghosts exist throughout the novel. Lockwood, the tenant of Thrushcross Grange, for example, is awoken by a startling dream of the ghost of Catherine.
Heathcliff, the tragic figure at the center of the novel, is an exemplar of a Byronic hero: an outsider motivated by intense obsession and revenge.
For these reasons, it is clear that Wuthering Heights is a Gothic novel; however, it is not correct to say that Wuthering Heights is a symbol of Gothicism. A symbol in literature is a literary device in which an object is used to stand in or exemplify another idea or concept. It would be more accurate to say that Wuthering Heights is a novel in the Gothic tradition of literature.

A symbol is an object, event, or person that represents something else in a work of literature, so while Wuthering Heights may not fit the bill of a symbol, technically speaking, the book certainly contains many elements that characterize Gothic literature.
In Wuthering Heights, the reader encounters a rundown castle in a rugged and inhospitable landscape, where a brooding, melancholy man lives a quiet life with few people around him. When the narrator, Mr. Lockwood, comes to this eerie place, he has terrible dreams about a ghost. Terrible weather conditions don't seem to shock or surprise Heathcliff, who is Mr. Lockwood's unfriendly host and the Byronic hero of the novel, as Heathcliff, himself, is haunted by a life of regrets and inner darkness. All of these mysterious elements meet the requirements of a Gothic novel, which means that Wuthering Heights represents a true Gothic work within the wider canon of Western literature.