Letter: K
- kernel-2.6.18-8.1.8.el5: The Linux kernel (the core of the Linux operating system)
- kernel-headers-2.6.18-8.1.8.el5: Header files for the Linux kernel for use by glibc
- kernel-xen-2.6.18-8.1.8.el5: The Linux kernel compiled for Xen VM operations