The title is deeply connected to Holden's disillusionment with maturation, and his desire to remove himself from society. He is most comfortable with children, as evident in the character of Phoebe. His greatest wish invovles being able to save children, perhaps from impending adulthood, which he explains in a dream:
"I keep picturing all these little kids playing some game in this big field of rye and all. Thousands of little kids, and nobody's around—nobody big, I mean—except me. And I'm standing on the edge of some crazy cliff. What I have to do, I have to catch everybody if they start to go over the cliff—I mean if they're running and they don't look where they're going. I have to come out from somewhere and catch them. That's all I'd do all day. I'd just be the catcher in the rye and all. I know it's crazy, but that's the only thing I'd really like to be. I know it's crazy."
Those last two sentences suggest that he knows he cannot continue his isolation, that he will never be able to be a savior of the kind he imagines. Also, the fact that he misinterprets the line (it's actually "when a body meets a body, coming through the rye"), shows that this dream, while noble in intention, can never be achieved in life.