RhymeZone: double-cross definitions

Definitions of double-cross:

verb: To betray or go back on.
verb: (plant breeding, animal breeding) To cross twice in hybridization, as (A × B) × (C × D); for example, in commercial hybrid seed corn, A through D are classically inbreds, and their grandoffspring is the seed for sale.

(Definitions from Wiktionary)