What is Silver Star?

Norman Bowker, in Tim's story, almost won the Silver Star--a medal for bravery--but was not quite brave enough. He left his friend Kiowa in the mud of the river bank, because the smell of the river was too disgusting for him to bear. When he returns home to America, he thinks about the Silver Star, and what it represents, and what bravery really means. He finds he cannot explain it to anyone, and getting or losing medals seems pointless when he thinks about Kiowa dying in that field.