(chemistry) Any of a group of seventeen soft, lustrous, sometimes magnetic metals that form trivalent salts; they include the lanthanides plus yttrium, scandium, thorium and sometimes zirconium.

(chemistry) A systematic name for an element, derived from the digits of its atomic number to which the suffix -(i)um is appended; normally only used for transuranic elements before or for a short period after they have been created, after which they will be given a non-systematic name.

(linear algebra) An element on the main diagonal of a square matrix, that is, an element in row k and column k where k is an integer between 1 and the number of rows (or columns) in the matrix.

(physics) A fundamental particle; any of the subatomic particles that do not consist of other, smaller particles; the gauge bosons, leptons and quarks.

(chemistry) Of, relating to, or being an element (as opposed to a compound). / Basic, fundamental or elementary. / Of the ancient supposed elements of earth, air, fire and water.

(theosophy, fantasy) A creature (usually a spirit) that is attuned with, or composed of, one of the classical elements: air, earth, fire and water or variations of them like ice, lightning, etc. They sometimes have unique proper names and sometimes are referred to as Air, Earth, Fire, or Water.

plural of element

Outdoor weather, such as wind or rain. / The basic tenets of an area of knowledge, basics, fundamentals. / The bread and wine of the Eucharist.

In a situation which is entirely suitable, familiar, or enjoyable.

Any part of a mechanism that exercises some form of logical control, such as a ratchet, trip, detent or interlock.