Final answer:
The M18 Claymore mine was standardized in 1956 and is an anti-personnel mine that releases shrapnel in a fan-shaped pattern, with its design and usage becoming a significant part of military history.
Step-by-step explanation:
The M18 Claymore mine was standardized by the United States Army in the year 1956. The Claymore is a directional anti-personnel mine that was designed to produce a directionalized, fan-shaped pattern of shrapnel. The development of the M18 Claymore began in the 1950s, and after several tests and modifications, it was officially adopted into military service. The Claymore's distinctive design and usage tactics have made it a significant topic in military history and its use has been widely adopted by other armed forces around the world.