Obelisk (noun)

A tall, four-sided, narrow tapering monument which ends in a pyramid-like shape at the top, typically made of stone and used as a memorial or marker.

Origin:

From latin obeliscus, from greek obeliskos "skewer, spit".

Examples:

1. The Washington Monument is an obelisk.
2. The ancient Egyptians used obelisks to mark the entrances of temples.
3. The obelisk was brought to Rome in ancient times.
4. The obelisk was originally covered in hieroglyphs.
5. The obelisk was made of granite.