The phrase "main pyramid" refers to the largest or most important pyramid in a group. It usually indicates that there are other smaller or less significant pyramids in the vicinity. Full definition
The site has several large structures including a tall main pyramid, along with beautifully preserved carvings. (travelandleisure.com)
But beneath the trash - strewn sand lies the main pyramid of a settlement called Aspero. (discovermagazine.com)
Although Chichen Itza's main pyramid may be one of the best in the whole Mayan world, Uxmal has 3 Pyramids — one of which you can still climb. (foodfuntravel.com)