Lubuntu is a lightweight Linux distribution based on Ubuntu, using the LXQt desktop environment in place of Ubuntu's GNOME desktop. Lubuntu was originally touted as being "lighter, less resource hungry and more energy-efficient", but now aims to be "a functional yet modular distribution focused on getting out of the way and letting users use their computer".
Lubuntu originally used the LXDE desktop, but moved to the LXQt desktop with the release of Lubuntu 18.10 in October 2018.
The name Lubuntu is a portmanteau of LXQt and Ubuntu. The LXQt name derives from the merger of the LXDE and Razor-qt projects, while the word Ubuntu means "humanity towards others" in the Zulu and Xhosa languages.