Oddly, a lot of folks refer to it that way, I’ve noticed. I s uh spect what they mean is the drop ship model that Shopify sorta pushes with partner apps, mainly because they simply don’t realize how many brands/stores are actually Shopify-hosted.
I can recognize it as a user myself and am honestly kinda starstruck when I see some big names using it.
But yes, it’s not it’s own marketplace, at all. Buyers can shop ON Shopify through a store site but not FROM Shopify itself.