[PaulHoule]

More generally partition (as a verb) means "to divide into parts" which is used for numerous purposes such as

-- to divide a country into parts (e.g. separate Pakistan and Bangladesh from India)

-- to divide a physical space with walls

-- to divide a population of molecules between molecules floating in the air and molecules stuck on walls

[tsimionescu]

Also to separate a computer network into two or more disconnected networks, the P in the CAP theorem stands for "partition tolerance" (i.e. that a system can keep working in case its components end up in a partitioned network).

[whatevertrevor]

-- "Divide" an integer into two or more integers that sum to it too. :D

[JadeNB]

The trivial partition n = n also usually counts as a partition. This is useful if you want to be able to dualize partitions, and want n = 1 + 1 + ... + 1 to have a dual partition.

[lazide]

Also to divide digital storage into individually addressable segments (disk partitions).