Definition of clefts:
(n) :
An opening, fissure, or V-shaped indentation made by or as if by splitting.
(n) :
A piece made by splitting.
(adj) :
split, divided, or partially divided into two.
(v) :
(linguistics) To syntactically separate a prominent constituent from the rest of the clause that concerns it, such as threat in "The threat which I saw but which he didn't see, was his downfall."
(n) :
A disease of horses; a crack on the band of the pastern.