Member Of Service (M.O.S.) is a term used in parts of the US for any

first responder A first responder is a person with specialized training who is among the first to arrive and provide assistance or incident resolution at the scene of an emergency, such as an accident, disaster, medical emergency, structure fire, crime, or terr ...

such as a police officer, firefighter, correction officer, emergency medical technician or paramedic. Originally used as an exclusive term by the (

New York City Police Department The New York City Police Department (NYPD), officially the City of New York Police Department, established on May 23, 1845, is the primary municipal law enforcement agency within the City of New York, the largest and one of the oldest in ...

), its use has expanded throughout the

northeast The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each se ...

to identify other types of emergency responders. The term is primarily used to identify an emergency responder in need of assistance. The M.O.S. in question may have been in a motor vehicle accident, an assault or shooting. The units responding usually get this information from their dispatcher after receiving a 911 or radio call for "M.O.S. needs help".

References

Emergency services in the United States {{emergency-stub