HDR has a number of different common meanings, which adds to the confusion.
For example, in video games, "HDR" has been around since the mid '00s, and refers to games that render a wider dynamic range than displays were capable of, and use post-process effects to simulate artifcats like bloom and pupil dilation.
In photography, HDR has almost the opposite meaning of what it does everywhere else. Long and multiple exposures are combined to create an image that has very little contrast, bringing out detail in a shot that would normally be lost in shadows or to overexposure.