This year, April 5 is Gold Star Spouses Day. What does it mean if you see a person wearing a Gold Star lapel pin? A tradition began during World War I, when a Blue Star banner hung in the windows of homes with a family member serving in the military. If that family member died during that service, the blue star was covered with a gold star.
A Gold Star lapel pin with a purple background, approved by Congress in 1947, is presented to the spouse of the member who lost their life in combat. A Next-of-Kin Gold Star button featuring a gold star on a gold background may be given to other family members.
Sources: https://veteran.com/gold-star-spouses-day/ and https://www.army.mil/goldstar/