look up any word, like cleveland steamer:
 
2.
When you are so intellectually stimulated your brain gets a boner.
You: Did you guys check out my new 3D TV?

Me: Yeah, major brain boner.

Used when describing something that intellectually "turned" you on.
by The Comet March 10, 2011
 
1.
Something that strikes a chord in someone's thinking, creating a spur of "enlightenment" and stimulation in knowledge, especially in subjects like philosophy & logic.
John: Hey, have you seen that recent philosophical discussion between XXX and YYY on YouTube?

Peter: Yeah, it was so good it gave me a brain boner.
by nullswitch February 20, 2011
 
3.
Sexual arousal that comes from enjoying someone else intelligence.
Guy1: Have you seen that girl? She is incredibly intelligent.
Guy2: Yeah, I would go over an horde of blood thirsty aliens to have her. I have an incredible Brain Boner.

Girl1: I can' t belive the way he explained Heisenber uncertainty principle.
Girl2: Yeah, he gave me a Brain Boner since the start of the class.
by Dolapevich January 17, 2014
 
4.
When you are talking and then have a random smart moment.
"Your mom just had a brain boner about robotics"
by Expression of happiness July 22, 2014
 
5.
A strong liking towards a member of the same gender, in a non-sexual manner. A closely bonded friendship. Similar to a "bromance."
Ted: "Hey where has Phil been lately? Ah, probably shackin' up with some lass."
Josh: "I really don't know and it's kinda bumming me out. We used to do everything together. It's kinda like Cheech without Chong."
Ted: "Heh sounds like you've got a total brain boner for him!"
by chungamunga April 18, 2009