What does Ubuntu Snappy mean?
Ubuntu Snappy is a package manager originally created by Canonical for the Ubuntu Phone distribution. Packages are called "snaps" and are designed to work across different Linux distributions, not just Ubuntu. The aim of the project is to create universal packages that work on any distribution, independent of any "app store."
Techopedia explains Ubuntu Snappy
Ubuntu Snappy is an attempt at creating a "universal package manager" for Linux distributions. Snappy is alternative to current package management systems like APT or RPM. With conventional package management systems, packages have to be adapted from the upstream source code. Some distributions make considerable changes to the code, which makes contributing upstream to the original open source project developers difficult.
Under Snappy, the packages are labeled "snaps." Snaps do not have any dependencies, which makes it possible to install snaps on distributions other than Ubuntu. While Snappy defaults to the Ubuntu app store, other repositories may be used. Snaps are also designed to be lightweight, with only changes to a snap, or deltas, installed on the system during upgrades.
Snappy was originally designed for Ubuntu Touch, but is available on the major distributions, including Debian, Fedora, CentOS and Arch Linux.