The first explanation of Wuthering Heights is given by Mr. Lockwood, who says,
"Wuthering" [is] 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.
This shows that Wuthering Heights is a place of extreme, harsh weather that leaves the landscape "stunted" by its force, as well as sharp and thorny, craving the scant sunlight. This description of the landscape serves as a metaphor for how the harsh, dysfunctional Earnshaw family living in Wuthering Heights stunts people like Catherine and Heathcliff, making them unusually "thorny," hard, and difficult people.
Later, when Lockwood asks Mrs. Dean about whether the Earnshaws are an old family, she says yes, and they discuss Heathcliff. A product of the rough environment of the isolated moors, he is, according to Nelly,
Rough as a saw-edge, and hard as whinstone! The less you meddle with him the better.
Wuthering Heights is also a name intimately connected with the moors. People on the moors, Nelly says again, are different from others, stronger, hardier, and more self reliant, because of the circumstances that have formed them. Both Catherine and Heathcliff, who spend so much time on the "wuthering" or windy moors, are "wild" children, according to Nelly.
Finally, Catherine shows the extent to which she is joined to the harsh, "wuthering" moors when she says to Nelly that she does not wish to go to a gentle heaven. She states,
I was only going to say that heaven did not seem to be my home; and I broke my heart with weeping to come back to earth; and the angels were so angry that they flung me out into the middle of the heath on the top of Wuthering Heights; where I woke sobbing for joy.
The formation the moors and Wuthering Heights offer set Catherine and Heathcliff apart. As Catherine goes on to explain to Nelly, she is different from people like Edgar, who are softer and more gentle because they have not had to face the harsh circumstances that she and Heathcliff have. The much more conventional Edgar is like the changeable foliage to her, while Heathcliff is, like her, made of the sterner rock of the moors.