1930s: The interjection "nerts", used because some consider it vulgar to blurt out "nuts", enjoys some popularity.
1940s: The singular "nert" evolves into a label applied to people, meaning someone who is nutty.
1950: Dr. Seuss tosses off the nonsense word "nerd" for an imaginary animal.
1951: Teen slang in the Detroit area is reported to have adopted "nerd" as the fashionable new term for an uncool unhip person, otherwise known as a "drip" or "square". This usage may or may not predate Dr. Seuss's, but it definitely spread from southeast Michigan.
1965: The spelling "nurd" comes into common use. The word is by now somewhat commonly connected with bookish intellectual types, but is still little known to most of the public. At MIT the spelling "gnurd" catches on. At this time, brainiacs at MIT and similar institutions are known for backward clothing styles and outmoded crewcuts. They also enjoy trashy science fiction.
circa 1972: I hear the word for the first time when my dad (a high IQ pocket-protected engineer who had only recently ceased rocking a crewcut) declares Batman to be a nerd. It briefly becomes my little brother's favorite new word.
1974: Happy Days debuts, and popularizes the term by using it as a piece of period slang, usually applying it not to smart or socially awkward characters, but to those who try to be cool and fail. Usage of the word aming viewers skyrockets.
1975: National Lampoon issues this poster
, clarifying what the word will now mean.
1977: Personal computers emerge into the mass market, which results in raising the visibility of computer and electronics experts as a recognizable social class, and over several years, accelerating the association of the word with them in particular. At the same time, Star Wars brings science fiction fandom into mainstream visibility.
1981: By now several computer innovators have achieved wealth and become household names, thereby becoming role models and getting people to start thinking of nerds as winners. This trend will expand steadily until the dot-com crash of 2000.
1984: Revenge Of The Nerds is released. People with technical interests and skills start to use the word as self-description with some regularity, with a "nerd pride" movement becoming visible a few years later.
1993: Professor Gerald Sussman, a former MIT hacker, tells a reporter "I want every child to become a nerd." And it's around this time that one of my nerd friends proclaims "It's our world now and you can't have it back!"
1995: The World Wide Web popularizes mass usage of computer networks. Non-experts start learning web development in large numbers, and produce the beginnings of today's distinct internet culture.
2003: San Diego Comic-Con grows with extreme rapidity, becoming the center of the various fandoms associated with nerds. The public becomes steadily more aware of the breadth of "nerd culture". Some people start to describe themselves as nerds or geeks based on their fandoms rather than on their skills -- that is, they define the label by what they consume rather than what they produce, even as these fandoms increasingly merge into the mainstream.
2007: The Big Bang Theory debuts, bringing the first broad depiction of all facets of nerd culture to a mass audience.
2012: As supposedly nerdy interests such as superheroes and wizards take over pop culture, jock types also move into technical fields. "Brogrammers" are now a thing.
2013: MovieBob Chipman points out that calling oneself a nerd has now become merely a "commodified lifestyle label", saying nothing about your temperament or skills or social history.