crossbill

noun

1. Any of various finches of the genus Loxia, whose bill crosses over at the tips; they are specialist feeders on conifer cones.
2. A bill brought by a defendant, in an equity or chancery suit, against the plaintiff, respecting the matter in question in that suit.

   “he not having the money ready[…] filed a bill for a specific performance, evidently to gain time. The vendors filed a crossbill; and afterwards the purchaser became a bankrupt”