Yeah no problem. It gets confusing because Lemmy, Kbin, Mastodon and the other big one I currently forget the name of are all their own set of software that people use to make their own instances with that can all talk to each other across the different instances and platforms but also, many of the big instances use the name of the software they use as part of their own name. ie mastodon.cloud (which is how you are presumably accessing this conversation) is a Mastodon instance (or whatever term is used for the Mastodon equivalent of a lemmy instance) but it is not Mastodon itself, just one example of Mastodon in action. Similarly in Lemmy-land you have major instances called beehaw.org (a Lemmy instance that my account is on and through which I am interacting with this post), lemmy.ml (which is the instance this post is actually on and is the oldest Lemmy instance run by the people who started the FOSS Lemmy project) and lemmy.world (the biggest Lemmy instance.) All three of those instances are run by entirely different people for different purposes and they all intercommunicate (to some degree, I think maybe beehaw.org currently is defederated from lemmy.world due to the challenges of moderating users from a large open instance in line with beehaw's goals), they are all Lemmy instances but none of them are actually the Lemmy FOSS itself. However, people often think that either lemmy.ml or lemmy.world is exactly synonymous with Lemmy or that beehaw.org is a seperate thing.
Really imo all the Fediverse stuff should have set a standard that would require consistent clear naming across all instances (IE, perhaps they could all be required to have an actual name independent of the name of the underlying technology and then also include what they actually are, ie beehaw-lemmy.org, beehaw-mastodon.org etc) but we're well past that point now I think.