The Collaborative International Dictionary of English v.0.48:

Silicon \Sil"i*con\, n. [See Silica.] (Chem.)
   A nonmetalic element analogous to carbon. It always occurs
   combined in nature, and is artificially obtained in the free
   state, usually as a dark brown amorphous powder, or as a dark
   crystalline substance with a meetallic luster. Its oxide is
   silica, or common quartz, and in this form, or as silicates,
   it is, next to oxygen, the most abundant element of the
   earth's crust. Silicon is characteristically the element of
   the mineral kingdom, as carbon is of the organic world.
   Symbol Si. Atomic weight 28. Called also silicium.
   [1913 Webster]

WordNet (r) 3.0 (2006):

silicon
    n 1: a tetravalent nonmetallic element; next to oxygen it is the
         most abundant element in the earth's crust; occurs in clay
         and feldspar and granite and quartz and sand; used as a
         semiconductor in transistors [syn: silicon, Si, atomic
         number 14]

The Elements (07Nov00):

silicon
Symbol: Si
Atomic number: 14
Atomic weight: 28.086
Metalloid element belonging to group 14 of the periodic table. It is the
second most abundant element in the Earth's crust, making up 25.7% of it
by weight. Chemically less reactive than carbon. First identified by
Lavoisier in 1787 and first isolated in 1823 by Berzelius.


The Jargon File (version 4.4.7, 29 Dec 2003):

silicon
 n.

    Hardware, esp. ICs or microprocessor-based computer systems (compare iron
    ). Contrasted with software. See also sandbender.


The Free On-line Dictionary of Computing (30 December 2018):

silicon

   1.  The material used as the base (or
   "substrate") for most integrated circuits.

   2.  Hardware, especially integrated circuits or
   microprocessor-based computer systems (compare iron).

   Contrast: software.  See also sandbender.

   [Jargon File]

   (1996-05-28)