1. [n]  an artifact that is one of the individual parts of which a composite entity is made up; especially a part that can be separated from or attached to a system; "spare components for cars"; "a component or constituent element of a system"
2. [n]  the most favorable environment for a plant or animal; "water is the element of fishes"
3. [n]  a straight line that generates a cylinder or cone
4. [n]  the situation in which you are happiest and most effective; "in your element"
5. [n]  any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter
6. [n]  one of four substances thought in ancient and medieval cosmology to constitute the physical universe; "the alchemists believed that there were four elements"

1. \El"e*ment\, n. [F. ['e]l['e]ment, L. elementum.]
   1. One of the simplest or essential parts or principles of
      which anything consists, or upon which the constitution or
      fundamental powers of anything are based.
   
   2. One of the ultimate, undecomposable constituents of any
      kind of matter. Specifically: (Chem.) A substance which
      cannot be decomposed into different kinds of matter by any
      means at present employed; as, the elements of water are
      oxygen and hydrogen.
   
   Note: The elements are naturally classified in several
         families or groups, as the group of the alkaline
         elements, the halogen group, and the like. They are
         roughly divided into two great classes, the metals, as
         sodium, calcium, etc., which form basic compounds, and
         the nonmetals or metalloids, as oxygen, sulphur,
         chlorine, which form acid compounds; but the
         distinction is only relative, and some, as arsenic,
         tin, aluminium, etc., form both acid and basic
         compounds. The essential fact regarding every element
         is its relative atomic weight or equivalent. When the
         elements are tabulated in the order of their ascending
         atomic weights, the arrangement constitutes the series
         of the Periodic law of Mendelejeff. See {Periodic law},
         under {Periodic}. This Periodic law enables us to
         predict the qualities of unknown elements. The number
         of elements known is about seventy-five, but the gaps
         in the Periodic law indicate the possibility of many
         more. Many of the elements with which we are familiar,
         as hydrogen, carbon, iron, gold, etc., have been
         recognized, by means of spectrum analysis, in the sun
         and the fixed stars. From certain evidence (as that
         afforded by the Periodic law, spectrum analysis, etc.)
         it appears that the chemical elements probably may not
         be simple bodies, but only very stable compounds of
         some simpler body or bodies. In formulas, the elements
         are designated by abbreviations of their names in Latin
         or New Latin. The Elements
         ------------------------------------------------------------
         Name |Sym-|Atomic Weight| |bol | O=16 | H=1 |
         ------------------------------------------------------------
         Aluminum | Al | 27.1 | 26.9| Antimony(Stibium) Argon
         Arsenic Barium Beryllium (see Glucinum) Bismuth Boron
         Bromine Cadmium Caesium Calcium Carbon Cerium Chlorine
         Chromium Cobalt Columbium Copper (Cuprum) Erbium
         Fluorine Gadolinium Gallium Germanium Glucinum
   
   

2. \El"e*ment\ ([e^]l"[-e]*m[e^]nt), v. t.
   1. To compound of elements or first principles. [Obs.]
      ``[Love] being elemented too.'' --Donne.
   
   2. To constitute; to make up with elements.
   
            His very soul was elemented of nothing but sadness.
                                                  --Walton.
   
   

1. One of the items of data in an array.

2. One kind of node in an sgml, html, or xml document tree. An SGML element is typically represented by a start tag ("") and an end tag (""). In some SGML implementations, some tags are omissible, as with "" in html.

The start tag can contain attributes (""), which are an unordered set of key-value bindings for that element. Both the start tag and end tag for an element typically contain the "tag name" (also called the "gi" or generic identifier) for that element.

In xml, an element is always represented either by an explicit start tag and end tag, or by an empty element tag ("").

Other kinds of SGML node are: a section of character data ("foo"), a comment (""), a markup declaration (""), or a processing instruction ("").