sulfur

noun

sul·​fur ˈsəl-fər 

variants or chiefly British sulphur

: a nonmetallic chemical element that is an essential element for all life, resembles oxygen in chemical properties, and is used especially in the form of sulfuric acid to extract phosphates from ores see Chemical Elements Table

sulfury adjective

or chiefly British sulphury

ˈsəl-fər-ē 

Is it sulfur or sulphur?: Usage Guide

The spelling sulfur predominates in U.S. technical usage, while both sulfur and sulphur are common in general usage. British usage tends to favor sulphur for all applications. The same pattern is seen in most of the words derived from sulfur.

Examples of sulfur in a Sentence

Recent Examples on the Web

The pH can be decreased with sulfur and increased with the use of lime. —Rita Perwich, San Diego Union-Tribune, 1 Mar. 2025

In July, El Sobrante managers informed the South Coast Air Quality Management District that a chemical reaction brewing inside the landfill was causing broiling temperatures and producing toxic sulfur pollution, according to air district records. —Tony Briscoe, Los Angeles Times, 28 Feb. 2025

Elemental sulfur exists as an eight-atom ring, and the reactions with lithium are slow enough that semi-stable intermediates with smaller chains of sulfur end up forming. —Ashley Belanger, Ars Technica, 17 Jan. 2025

For example, sulfur aerosols are emitted by ship engines and power plants. —Annalisa Bracco, The Conversation, 9 Jan. 2025

Word History

Etymology

Middle English sulphur brimstone, from Latin sulpur, sulphur, sulfur

First Known Use

14th century, in the meaning defined above

Phrases Containing sulfur

• sulfur bacterium
• sulfur dioxide
• sulfur mushroom
• sulfur polypore
• sulfur shelf

Rhymes for sulfur

• sulphur

Kids Definition

sulfur

noun

sul·​fur

variants also sulphur

ˈsəl-fər 

: a nonmetallic element that occurs either free or combined especially in sulfides and sulfates, is found in proteins, exists in several forms including yellow crystals, and is used especially in the chemical and paper industries, in strengthening rubber, and in medicine for treating skin diseases see element

Medical Definition

sulfur

1 of 2 noun

sul·​fur

variants or chiefly British sulphur

ˈsəl-fər 

: a nonmetallic element that occurs either free or combined especially in sulfides and sulfates, is a constituent of proteins, exists in several allotropic forms including yellow orthorhombic crystals, resembles oxygen chemically but is less active and more acidic, and is used especially in the chemical and paper industries, in rubber vulcanization, and in medicine for treating skin diseases

—symbol S see Chemical Elements Table

sulfur

2 of 2 adjective

variants or chiefly British sulphur

: of, relating to, or resembling sulfur : containing or impregnated with sulfur