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

Wake up with the distinct call of the Asian koel and walk the silica shores as hermit crabs scuttle by and baby blacktip reef sharks play in the lapping waves. —Katie Lockhart, Travel + Leisure, 7 Sep. 2025

Scientists use superfine silica to block battery hazards Inspired by the behavior of oobleck, Gabriel Veith and his team aimed to make lithium-ion batteries safer by adding an impact-resistant material to the electrolyte. —Bojan Stojkovski, Interesting Engineering, 6 Sep. 2025

Not only does this sunscreen contain two minerals, it’s also formulated with vitamin E, which nourishes the skin, silica, an oil-absorbing powder, and spring water (sourced from the city of La Roche-Posay in France) to soothe the skin barrier. —Gabrielle Marchese, Outside, 28 Aug. 2025

Others rely on abrasive agents like silica to mask surface stains. —Daryl Austin, Forbes.com, 14 Aug. 2025

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