I disagree with slhck's answer. The OP refers to the Linux kernel and, in such matters, the first reference is the Linux Kernel Organization, which
... is managed by The Linux Foundation, which provides full technical, financial and staffing support for running and maintaining the kernel.org infrastructure.
The Linux Kernel site identifies the version with the progressive number, like anything preceding the dash in the output below,
$ uname -r
i.e. 3.16.0. At the same time, it identifies the release as one category among five. The first four are:
Prepatch or "RC" kernels are mainline kernel pre-releases that are mostly aimed at other kernel developers and Linux enthusiasts. They must be compiled from source and usually contain new features that must be tested before they can be put into a stable release. Prepatch kernels are maintained and released by Linus Torvalds.
Mainline tree is maintained by Linus Torvalds. It's the tree where all new features are introduced and where all the exciting new development happens. New mainline kernels are released every 2-3 months.
After each mainline kernel is released, it is considered "stable." Any bug fixes for a stable kernel are backported from the mainline tree and applied by a designated stable kernel maintainer. There are usually only a few bugfix kernel releases until next mainline kernel becomes available -- unless it is designated a "longterm maintenance kernel." Stable kernel updates are released on as-needed basis, usually 2-3 a month.
There are usually several "longterm maintenance" kernel releases provided for the purposes of backporting bugfixes for older kernel trees. Only important bugfixes are applied to such kernels and they don't usually see very frequent releases, especially for older trees.
These are the official release designations. However, you are unlikely to have any of those, because there is also a fifth kind of release. Again as per the previously referenced page,
Many Linux distributions provide their own "longterm maintenance" kernels that may or may not be based on those maintained by kernel developers. These kernel releases are not hosted at kernel.org and kernel developers can provide no support for them.
It is easy to tell if you are running a distribution kernel. Unless you downloaded, compiled and installed your own version of kernel from kernel.org, you are running a distribution kernel. To find out the version of your kernel, run uname -r:
# uname -r
If you see anything at all after the dash, you are running a distribution kernel. Please use the support channels offered by your distribution vendor to obtain kernel support.
If you want to know which official release your distro-customised kernel is based upon, there is one such list on the Linux Kernel main page.