No, that's just irrelevant background. An infodump is when story-necessary details are all lumped into one big delivery instead of integrated organically into the story where they would naturally occur (as "natural" as an artificially created story can be, that is). One of the old phrases in the genre writing community is "As you know, Bob," which mimics the typical start to such an infodump: one character explaining to another things they already know, purely for the purpose of delivering the information/background to the reader.
This is, of course, far too broad a generalization; good writers very often find ways of dumping a lot of story-necessary information at once without resorting to hamfisted "As you know, Bob" approaches, and nobody honestly thinks of those as infodumps. It's really a question of how deftly or clumsily the massive flow of information is woven into the effect of an organically developing plot/scene.
It's one of the reasons Bob was created, as far as I recall, as related by Jim. A good example in the story is Bob explaining the different types of werewolves in
Fool Moon. It's justified within the story (Harry is asking him about it, and Bob talks for a few pages about them), so it avoids the kind of thing like, "As you know, Harry, there are four types of werewolves..."
Some like to use it to shoehorn characterization into a short scene. Christopher Nolan is bad about that. Watch
Interstellar—way at the beginning, Michael Caine starts waxing poetical about how Matthew McCoughenaheralery was a brilliant engineer, and how he's frustrated that he was born into the wrong age and forced to go into agriculture, and so on. It overlaps with "show, don't tell"-related concepts (where this is telling rather than showing), similar to statements that start with "That makes me feel..."
Regular infodumps are possibly best exemplified by The Architect scene from the end of
The Matrix Reloaded. He provides information relevant to the story and the universe in which it is set, explains a bunch of stuff, and then the story moves on.
