A pin has a head and no eye, a needle has an eye and no head, and the needle is the half that hangs on a thread.
There’s one that has a head without an eye, and there’s one that has an eye without a head. You may find the answer if you try, and when all is said, half the answer hangs upon a thread. What are they?
Give me a hintThe hint
Look in a sewing box.
Reveal the answerHide the answer
A pin and a needle
Source: Christina Rossetti, Sing-Song: A Nursery Rhyme Book, 1872