The Klingon ritual under which the victor in honourable combat may marry the widow of the man he killed and so become head of the dead man's House.
Brek'tal is a provision of Klingon custom. When the head of a House is killed in personal combat, the widow may marry the victor, who then takes the dead man's place as leader of the House.
It is used in The House of Quark in 2371. A drunken Klingon named Kozak falls on his own knife in Quark's bar, and Quark boosts business by claiming he killed him in a fight. Kozak left no male heir, and his rival D'Ghor stands to seize the House. The widow, Grilka, therefore carries Quark off to the homeworld and marries him at knifepoint under brek'tal.
Quark goes on to expose D'Ghor's financial scheming before the High Council and to face him unarmed, shaming him. Gowron grants Grilka the right to lead her House herself, and she divorces Quark with thanks.