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

Many of the materials needed for producing chips are byproducts of crude oil and natural gas processing, such as helium, bromine, and sulfur. —Miranda Jeyaretnam, Time, 15 May 2026

The bacteria’s digestion produces toxic sulfur as a by-product, however. —Adam Kovac, Scientific American, 15 May 2026

Molecule stops energy loss One of the biggest challenges in lithium-sulfur batteries is the formation of soluble intermediate compounds during operation. —Neetika Walter, Interesting Engineering, 12 May 2026

All of these plants benefit from the sulfur-like compounds that are found in onions and which deter an assortment of common garden pests. —Lauren Landers, The Spruce, 10 May 2026

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