The things that make up a collection are called elements or members.
The elements of records are usually called fields or members.
A group is a set (collection) G whose members are called elements.
The elements of the center are sometimes called central.
Alchemy is a study of the basic elements called fire, water, earth and air.
Two or more elements in this relationship are called tuples.
For a period of time, element 106 was called Unnilhexium.
Like a set, it contains members (also called elements, or terms).
For example, there is an element called americium-241 which gives off alpha radiation.
These elements are called the control plane and the data plane.