Both Uses of

cleave
in
Wuthering Heights

I explained that they were bare masses of stone, with hardly enough earth in their clefts to nourish a stunted tree.†
p. 138.2 *

clefts = splits or cracks

My heart invariably cleaved to the master's, in preference to Catherine's side: with reason I imagined, for he was kind, and trustful, and honourable; and she — she could not be called OPPOSITE, yet she seemed to allow herself such wide latitude, that I had little faith in her principles, and still less sympathy for her feelings.†
p. 77.9

Definitions:

(1) (cleave as in: cleave through)
to split or cut through something

Ironically, this word can mean to split in two or to hold together.

Note that you may see cleaved, cleft, clove, or cloven as the past tense of this sense of cleave.
(2) (cleave as in: cleave to)
to hold firmly to something -- such as an object, a person or idea

Ironically, this word can mean to split in two or to hold together.

Note that you may see cleaved, clove, or clave as the past tense of this sense of cleave.
(3) (meaning too rare to warrant focus)
meaning too rare to warrant focus:

a proper noun or other word too rare to warrant focus