The Floor of a Fireplace
Puzzle 9 of Justin Timberlake Piece of Cake Pack
Question is: The Floor of a Fireplace
and the answer is: HEARTH
Word Meaning:
HEARTH — The place in a home where a fire is or was traditionally kept for home heating and for cooking, usually constituted by at least a hearthstone and often enclosed to varying degrees by any combination of reredos, fireplace, oven, smoke hood, or chimney.
Definitions from Wiktionary.