Crossover

In generative syntax, establishing a relation between two elements across another element which somehow interferes with that relation. The name crossover derives from Ross's Crossover Condition:


 * No NP mentioned in the structural index of a transformation may be reordered by that rule in such a way as to cross over a co-referential NP. (Ross 1967:73)

Example
This condition accounts for the ill-formedness of the following sentence: the NP which has been moved across the co-referential NP it.

* The pudding whichi the man who ordered iti said ti would be tasty was a horror show.

Subtypes
Two subcases distinguished are strong crossover and weak crossover.

Link
Utrecht Lexicon of Linguistics