Bitcoin is a scarce digital asset that can be sent securely over the internet without needing an intermediary.
Bitcoin was launched in 2009 by an anonymous developer/group of developers who called themselves Satoshi Nakamoto. Satoshi saw the problems with modern, centralized monetary policy and the resulting inflation of "fiat" (or government-issued) monies.
Understanding that we needed a better, sound money for the internet, which couldn't be artificially inflated or controlled, Satoshi created bitcoin.
Bitcoin can be described as "digital gold," in that it is scarce, fungible, divisible, and easily transmittable.