The process of moving something to a centre, normally before some other process.
A type of formwork which serves as a temporary structure during the construction of arches and bridges.
A prewriting technique consisting of writing ideas down on a sheet of paper around a central idea within a circle, with the related ideas radially joined to the circle using rays.
The undesirable contiguous grouping of elements in a hash table.
A grouping of a number of similar things.
The grouping of a population based on ethnicity, economics or religion.
Forming a cluster.