Why are my Gmail and Yahoo email accounts combined on my iPad and iMac?

Sometime in the past few months, my yahoo emails started being combined in my gmail accounts. This happens in Mail on both my iMac and iPad ( I don't have an iPhone). I have never messed with the settings and I verified the settings are correct. This is not happening on my actual gmail account through Google.

My set up is for two accounts: Gmail and Yahoo. My Yahoo email has no such issues.

Thanks!