silica

noun

sil·​i·​ca ˈsi-li-kə 

: the dioxide of silicon SiO₂ occurring in crystalline, amorphous, and impure forms (as in quartz, opal, and sand respectively)

Examples of silica in a Sentence

Recent Examples on the Web

Made with oil-absorbing ingredients, including silica and methyl methacrylate cross polymer, the sunscreen also has humectants and emollients. —Jenny Berg, InStyle, 29 May 2026

Modern cement production begins primarily with limestone (calcium carbonate, CaCO₃) and silica-rich minerals such as clay or sand. —New Atlas, 26 May 2026

The technique exploits a material’s crystal structure to create nanoscale patterns directly onto hard materials used in devices, including silica. —Prabhat Ranjan Mishra, Interesting Engineering, 24 May 2026

The oil-free, non-comedogenic, chemical formula won’t clog pores, while silica and perlite absorb excess shine, leaving behind a matte finish that keeps midday slickness in check. —Christa Joanna Lee, Allure, 22 May 2026

Word History

Etymology

New Latin, from Latin silic-, silex hard stone, flint

First Known Use

circa 1801, in the meaning defined above

Phrases Containing silica

• silica gel
• vitreous silica

Rhymes for silica

• basilica

Kids Definition

silica

noun

sil·​i·​ca ˈsil-i-kə 

: a compound that consists of the dioxide of silicon and occurs in various forms (as in quartz, opal, and sand)

Medical Definition

silica

noun

sil·​i·​ca ˈsil-i-kə 

: the dioxide of silicon SiO₂ that is used as an ingredient of simethicone and that occurs naturally in crystalline, amorphous, and impure forms (as in quartz, opal, and sand respectively)

called also silicon dioxide