APB or "all-points bulletin" is a term used by authorities when an urgent message is sent out to law enforcement officers about a suspected criminal. However, there are several synonyms for APB that can be used in different contexts. These include "BOLO" or "be on the lookout," which is commonly used to alert officials about a potential danger or missing person. Another synonym is "Silver Alert," which specifically refers to an urgent notice for a missing or endangered senior citizen. Other related terms are "BOA" or "be on alert," "wanted bulletin," and "urgent notice." It is essential to know these synonyms to communicate effectively in emergencies.