How is the title Wuthering Heights relevant to the novel?

Wuthering Heights is named for the home and farm where much of the action of the novel takes place. This location is central and formative to Catherine's and Heathcliff's lives, the main characters in the novel.
Catherine and Heathcliff grow up in this rugged stone sixteenth century house where they face the abuse and neglect that forms their characters. Here they become strong-willed, courageous, and hardy—and, to some extent, almost savage. In many ways, the house itself, rough-hewn and unpolished, reflects the souls of these two characters.
This home and the adjoining wild moors are where Catherine and Heathcliff grow close and fall in love. The moors—windy or "wuthering" like the landscape surrounding the house—become an extension of their home because they spend so much time outside to escape the family dysfunction.
As Nelly Dean points out, people from Yorkshire (the northern part of England) are different from the gentler souls who live and grow up in more inviting places. Catherine and Heathcliff exemplify this hardiness and depth—the roots of their love are deep and intertwined.