In season one of Charmed Leo describes his bosses as "Elder Whitelighters" and says they are called "The Founders". The next time we hear a name for his bosses, they are called "The Elders". It is generally believed that these are the same, though never officially confirmed, so some people play around with the idea that they aren't. If they are the same, then The Elders are elder whitelighters, which in most cases, the known exception being Kevin, they were once whitelighters and although the bosses of whitelighters, they are a subcategory of whitelighter.
"Also known at the Founders, they are the highest level of Whitelighter. The Elders control the ranks of the guardian angels and keep track of the good witches they protect. They are not all-knowing but they can aid with their vast wisdom."