decagon
nounUK /ˈdɛkəɡən/
US /ˈdɛkəɡɑːn/
A decagon is a flat shape with ten straight sides.
The stop sign in our neighborhood is shaped like a decagon.
OTHER MEANINGS
2. A ten-sided regular polygon with equal sides and equal angles.
The mathematician drew a regular decagon inside the circle.
3. A decorative tile or mosaic piece with ten sides.
The floor was covered with colorful decagons.
4. A ten-sided architectural feature, such as a room or tower.
The old library had a decagon-shaped reading room.