Horizontal Beam of Timber That Supports a Window
Puzzle 16 of Building a House Hard Pack
Question is: Horizontal Beam of Timber That Supports a Window
and the answer is: LINTEL
Word Meaning:
LINTEL — (architecture) A horizontal structural beam spanning an opening, such as between the uprights of a door or a window, and which supports the wall above.
Definitions from Wiktionary.