Cross-Claim / Cross-Complaint

A pleading which asserts a claim arising out of the same subject action as the original complaint against a co-party, i.e., one co-defendant cross claims against another co-defendant for contribution for any damages assessed against him.

Source: U.S. Courts

A claim filed by codefendant(s) or coplaintiff(s) against each other. (Compare with counterclaim.)

Source: California Courts.