To verify or confirm information by comparing it with other sources. The editor asked the journalist to cross-check the facts before publishing the article.
In ice hockey, to hit an opponent with the stick held in both hands and no part of the stick on the ice. The player was penalized for cross-checking his opponent during the game.
In chess, to answer a check by giving a check to the opposing king. He cross-checked on the next move, turning the tables and securing equality.