In the same way everywhere, or to the same degree throughout — with no part different from any other. It has two everyday jobs. First, it describes how something is spread or done: spread the butter uniformly, heat the pan uniformly, the rule is applied uniformly to all students. Here it means evenly, with nothing thicker or thinner, no favourites. You will see it a lot in science writing, cooking instructions, and rules, because "evenly" sometimes sounds too casual. Second — and this one surprises learners — it works as an intensifier before an adjective, meaning "every single one, without exception": the reviews were uniformly good, the response was uniformly negative, her students were uniformly polite. Notice that this use is about a group of separate things all landing the same way, and it quietly says the writer checked and found no exceptions. That makes it stronger than "generally" or "mostly". It is a formal-leaning word. In speech most people would say evenly, or all of them were, or across the board. In writing it is very much at home.