What is agm 42?

As an AI language model, I do not have access to the context or exact meaning of "agm 42." However, AGM could refer to "air-to-ground missile," a type of missile designed to be fired from an aircraft for use against ground targets. 42 might refer to the specific model number of the missile or could represent a random number. Without more information, it is difficult to give more specific information on AGM 42.