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

Workers believe two of their colleagues died from a preventable lung disease caused by inhaling silica dust while working on the New Jersey temple, the largest such building outside of India. — Frank Andrews, CBS News, 8 Sep. 2026

Amorphous silica, for example, was released into the New York City subway in 2016, as part of a Department of Homeland Security test designed to simulate the impacts of a potential biological attack. — Laura Paddison, CNN Money, 8 Sep. 2026

Firefighters hacked through wood, slate and concrete trench lines, a process the Reserve Organization of America says likely generated silica-containing dust. — Karissa Waddick, USA Today, 6 Sep. 2026

Conventional silica fiber is usually cylindrical, a geometry that works particularly well for measuring forces acting along the fiber. — Pawel Maniewski, New Atlas, 2 Sep. 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