Curious about the difference? First definition for “geek” in Merriam-Webster’s dictionary:
1: a carnival performer often billed as a wild man whose act usually includes biting the head off a live chicken or snake
In contrast, “nerd” originates with M. Theodore Geisel, aka Dr. Seuss:
The American Heritage Dictionary in fact credits Dr. Seuss as the originator of the word nerd, which made its first appearance in his 1950 book, If I Ran the Zoo: “And then just to show them, I’ll sail to Ka-Troo And Bring Back an It-Kutch a Preep and a Proo a Nerkle a Nerd and a Seersucker, too!”
So that clears that up.