Double check

inspect or check again, look over a second time, check twice

inspected or checked again, looked over a second time, checked twice

There is also Double Check (novel), a novel in the Traces series by Malcolm Rose. In chess, a double check is a check delivered by two pieces at the same time.The most common form of one check involves one piece moving to deliver check, at the same time revealing a discovered check from a piece behind (such a check is an inherent part of the type of smothered mate known as Philidor's legacy). The only replies to a double check are king moves, as capturing the checking piece (except by the king, which in the process moves out of check-by-the-other-piece) is not an option since there are two of them, and interposition is likewise impossible as there would be two lines of attack to block. Exceptionally, the piece moved does not have to give check. The only way for this to happen in orthodox chess is by way of an en passant pawn capture. In the position shown to the right, Black has just played g7-g5; white replies hxg6 e.p.+. This is a double check, yet the pawn moved does not give check: one check is given by the rook, the other by the bishop; the former is discovered by the movement of the capturing pawn, the latter by that of the captured pawn. Such a double check is extremely rare in practical play, but is sometimes found in problems.
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Noun
1. something that checks the correctness of a previous check
(synonym) countercheck
(hypernym) assay, check
(derivation) double-check

Verb
1. check once more to be absolutely sure
(hypernym) see, check, insure, see to it, ensure, control, ascertain, assure
(derivation) countercheck, double check

check again to be sure something is correct He double-checked the price of the airplane ticket.

Synonyms and related words:
audit, balance, balance the books, check, check and doublecheck, check out, check over, collate, confirm, cross-check, demonstrate, inventory, overhaul, prove, recheck, take stock, test, triple-check, validate, verify,