Noun - A moment in time where a person's perspective and/or opinion is quickly and forcefully shot down, with or without good reason to do so. Usually the words "knowledge bomb" are spoken just after the incident in a falsetto voice.
Can also be used in verb form (i.e. He just got knowledge bombed, or KB'd).
"I'm trying to raise money for college." -Deb
"Your mom goes to college! Knowledge bomb..." -Kip Dynamite