[ 'sɪlɪkə ]
■ noun silicon dioxide, a hard, unreactive, colourless compound which occurs as quartz and as the principal constituent of sandstone and other rocks. [SiO 2 .]
Derivatives
siliceous sɪ'lɪʃəs (also silicious ) adjective
Origin
C19: from L. silex , silic- 'flint', on the pattern of words such as alumina .