Support for input using SI prefixes was [added to the Monero codebase](https://github.com/monero-project/monero/pull/1826) on March 3, 2017 by [Moneromooo](https://github.com/moneromooo-monero). The smallest unit of Monero (10^-12 XMR) was originally called a tacoshi in honor of user [Tacotime](https://bitcointalk.org/index.php?action=profile;u=19270), an early Monero contributor and was later renamed for ease of use and consistancy.