For much of the 70, 80s, and even 90s, “nerds” and “geeks” were synonymous for most who used the terms. The words could be interchanged and nobody would give it a thought. After the turn of the millennium, it became clear that the two groups became distinct (if they weren’t already) and headed in different but parallel directions.
To understand the distinctions, we refer to the graphic below that makes the question easier to answer. Click to enlarge.