What does wishbone mean in this Robert Frost quote?
A wishbone is a Y-shaped bone in turkeys, geese, etc. A common superstition is that if two people make a wish and pull a wishbone apart with each person holding a branch of the "Y," the person who ends up with the longer portion will have his or her wish come true.
Frost is using this idea as a metaphor for wishing, just like people sometimes use funnybone as a metaphor for the sense of humor (e.g., "That joke tickled my funnybone."). So this quote is saying that many people spend their whole lives wishing for things (but perhaps never acting to fulfill their wishes).