What are the various parts of the Kernel version number?
Lets look at a recent stable kernel version: 2.4.19
There are three parts to the version number:
Major number 2.4.19: represents very significant changes
Minor number 2.4.19: Release, even numbers are production and odd numbers are development
Micro number/Patch level 2.4.19: bug fixes and updates. Some references designate the third number as the micro number and add a -<patchlevel> to the version number, e.g. 2.4.18-3.
Note: Version numbers of distributions are independent of kernel version
E.g. Red Hat 8.0 contains Linux Kernel 2.4.18