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

This naturally occurring pigment is composed of iron oxide, clay, and silica and has been used by several species of hominins for thousands of years. —Laura Baisas, Popular Science, 16 Apr. 2025

Black lung, a debilitating and often fatal condition caused by inhalation of coal and silica dust during mining, affects roughly 1 in 5 miners who have worked in the Central Appalachian mines for twenty-five years or more, according to NIOSH. —Dr. Mark Abdelmalek, ABC News, 10 Apr. 2025

Exposure to silica dust can cause severe lung disease. —Rachel Frazin, The Hill, 1 Apr. 2025

Substances such as silica, gypsum, perchlorates and nanophase iron oxides contained in Martian dust could have life-threatening effects on members of a potential Mars mission, according to a study published in the journal GeoHealth last month. —Jack Guy, CNN Money, 26 Mar. 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