what is the meaning of the title "the catcher in the rye"?

It comes from the Robert Burns song "Comin' Through the Rye". Holden has these strange visions of being a catcher, catching children "comin' through the rye". Pax - C.

in the story, holden says that his dream profession is being a "catcher in the rye".. i dont remember the exact words but he says this when he is talking to Mr. Antolini. he says that children would be playing and he (holden) would be standing at the end of a cliff catching children before they fall. it kind of relates to holdens life.. he's been through a lot without anyone to "catch him."

hope this helped [=

Besides the whole meaning already explaining it should be also mentioned the symbolism behind

Holden doesn't want the kids to "fall" (e.g. corrupted by the world) while they are playing (being kids)

Ergo, he wants them to be innocents as long they can; unlike that him that grew up fast and is now a bitter person