kernel
The core of the operating system - manages memory and hardware resources(including the processor and the memory), loads processes and libraries, schedules threads for execution.
The kernel runs with a higher privilege than other programs (so-called user-mode programs). The power and robustness of an OS's kernel play a major role in shaping overall system design and reliability.

A kernel connects the application software to the hardware of a computer.
Symbian OS's Kernel is called EKERN.EXE.

kernel object
An object that is created and managed in the address space of the OS kernel, rather than of an individual process.

key
A value constructed from one or more columns in a row, which can be used to identify the row within an index.
See also: column, row, index

key event
An event from the window server indicating a key down, repeat or up.
See also: window server, pointer event

keyboard focus
Any particular key event is sent only to one window group. This is the group that has current keyboard focus.
See also: window group

keyboard repeat rate
The time interval between repeated key events generated by the window server. There are two settings involved: the initial delay before the first repeat event is generated, and the interval between subsequent events.
See also: auto-repeat

keyspace
In Symbian OS, a subsection of the central repository that contains the settings managed by one particular application.