rift 1 
(rĭft)
(rĭft)n.
1. A fissure, crack, or opening, as in rock.
2. A break in friendly relations: a rift between siblings.
3. Geology An area where the lithosphere is thinning, typically associated with large faults and grabens.
v. rift·ed, rift·ing, rifts
v.intr.
To split open; break.
v.tr.
To cause to split open or break.
[Middle English, of Scandinavian origin.]