A charge was a type of explosive weapon. Numerous types of charges existed for a variety of applications - from small scale damage to ship-to-ship confrontations.
In 2370 an away team from the USS Enterprise-D was armed with cases of charges to be put in place to destroy a complex utilised by a conspiracy within Starfleet. The team put the charges in place, but when the time came to detonate them found they had no effect as the conspirators had been able to disarm them moments after they had been set. (TNG comic: "An Inconvenient Truth")
In the alternate reality created by the temporal displacement of the Narada, bomber-type vessels, such as the Federation Defender-class and Romulan Cetratus-class, were armed with explosive charges. (TOS video game: D-A-C)