What does "split to" mean in regards to breeding colors?

[Oblio13]

For example, what does this mean? It comes from a Muscovy breeder's site.

"Black males (split to chocolate) and Chocolate females"

 

[IvysAnimals]

It means they'll look black, but they can produce black or "chocolate" colored offspring and the female will be in the chocolate color.

 

[JacinLarkwell]

If bred to another split of the same color or the actual color, they will produce that color in a portion of their offspring.

Basically, they're heterozygous for a recessive color