Final answer:
A gold star on a service flag during World War II signified that a family member had died in the war, symbolizing sacrifice and loss.
Step-by-step explanation:
During World War II, families with members serving in the military often displayed a service flag in the window of their homes. A flag with a gold star indicated that a family member had died in the war. The use of this symbol was a poignant reminder of the sacrifice made by that individual and the loss felt by the family. This practice was part of the broader context of the American home front where civilians contributed to the war effort, experienced the stresses and strains of having loved ones in danger, and faced the reality of those who would not return.