The word means peace or undisturbed.
In Tim O'Briens chapter good form, the narrator says he wants his readers to feel WHAT HE FELT.
Even though I haven't read the whole story, I think he is using the first person point of view in telling his story. This is because in using the first person point of view, readers will be able to put themselves in the narrator's shoes and experience what is happening in the story.
Me: Hey, you know that Children's day is near right? I was wondering if we could ask the school to organize a feeding program to the kids in the slum area near our school
Friend: Yeah and that's a good idea. We should probably talk to the principal.
Me: That's what I thought. Let's head over to her office and ask if we could talk to her.
Friend: Let's do it! I'm sure the principal will think it's a good idea.