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

Long-wearing ingredients like synthetic beeswax, silica, and vitamin E help the formula stay smooth, crease-resistant, and comfortable all day. —Christa Joanna Lee, Allure, 29 Oct. 2025

Radiolarians are adept at distilling silica, a form of quartz, from seawater, a process known as biomineralization. —Literary Hub, 28 Oct. 2025

The result was a graphene-silica fiber membrane (G@SFM), a cloth-like material that is both lightweight and thermally stable. —Kapil Kajal, Interesting Engineering, 24 Oct. 2025

Hippopotomonstrosesquipedaliophobia — fear of long words (The longest word found in major English dictionaries is pneumonoultramicroscopicsilicovolcanoconiosis, a 45-letter word describing a lung disease caused by inhaling fine silica dust. —Scott Lafee, San Diego Union-Tribune, 21 Oct. 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