The inescapable general baseline knowledge of fandoms even if you are nottechnically a part of the fandom, that you gained from being a nerd and talking to other nerds.
Person 1: How did you know so much about Doctor Who?
Person 2: Oh that, I got it from Base Line Nerd Osmosis with my sister.
A person who plays video games A LOT. Usually they have no job, live with their parents, and spend the majority of the time playing it.
A lot of Game Nerds try to change the definition of the word 'game nerd' to someone who knows a lot about videos games, but they are just embarassed to embrace the fact that their only hobby is clicking buttons.
One of the biggest game nerds I know is named jose.
A skater that is so obsessed with skateboarding he eats, breaths, and sleeps skating As By downloading Podcasts, video and rating other skaters on who they skate.