Yes that is considered a backlink. But it’s not a stupid question, the SEO world is filled with terminology that makes little sense, and that in some cases is just wrong and confusing.
Backlink is a good example, I mean, it would make sense to call it a backlink if you where both linking to each other, that would make it “a link back”. But that’s not what people mean when they talk about backlinks.
At my agency we never use the term backlink, since it’s confusing and not accurate. We talk about internal and external links. Which is a lot more accurate.
Another perfect example of SEO terminology being weird and confusing is the term long tail keywords, since it implies there being a short tail as well. It’s weird how people often divide keywords into Head, Body and Longtail, which is confusing, because where is the short tail then? Head Body and Tail would make so much more sense.
As I said, the SEO world is filled with examples like these. So don’t feel stupid when asking about these things, because they don’t make sense from a linguistic point of view.