Solid with triangular sides (7)

I believe the answer is:

pyramid

(Other definitions for pyramid that I've seen before include "Four sided monument" , "type of selling" , "old tomb" , "Form of ancient Egyptian royal tomb" , "Massive Egyptian memorial" .)

I've seen this clue in The Independent.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.