for The Hardest Word by Jacqueline Jules and Katherine Janus Kahn
The Ziz, a wonderful bird who lived long ago, is so big and clumsy that he can't keep from bumping into things. When a tree he knocks over destroys the children's garden, he seeks God's help to fix things. "Bring me the hardest word," God instructs him, and the Ziz flies off to search. He brings back words like rhinocerous, rock, and Rumplestiltskin, but none is acceptable, until he makes an important discovery.
Publisher description retrieved from Google Books.