Final answer:
The Gold Star Lapel Button was established by an Act of Congress, Public Law 80-306, in 1947 to honor the next of kin of U.S. Armed Forces members who lost their lives in active military service.
Step-by-step explanation:
The law establishing lapel buttons for next of kin of service members who have lost their lives while on active duty is known as Gold Star Lapel Button. This button is a symbol of the family's sacrifice and is presented to the immediate family members of the fallen servicemember. The tradition of the Gold Star began during World War I and the lapel buttons were formally authorized by an Act of Congress, Public Law 80-306, which was passed in 1947. The observance of this tradition serves as a way to honor those who have paid the ultimate sacrifice while serving the nation.