sulfur

American  

[suhl-fer] / ˈsʌl fər /

noun

1. Chemistry. Also a nonmetallic element that exists in several forms, the ordinary one being a yellow rhombic crystalline solid, and that burns with a blue flame and a suffocating odor: used especially in making gunpowder and matches, in medicine, in vulcanizing rubber, etc. S; 32.064; 16; 2.07 at 20° C.

2. sulphur.

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sulfur British  

/ ˈsʌlfə /

noun

1. the US preferred spelling of sulphur

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sulfur Scientific  

/ sŭl′fər /

1. A pale-yellow, brittle nonmetallic element that occurs widely in nature, especially in volcanic deposits, minerals, natural gas, and petroleum. It is used to make gunpowder and fertilizer, to vulcanize rubber, and to produce sulfuric acid. Atomic number 16; atomic weight 32.066; melting point (rhombic) 112.8°C; (monoclinic) 119.0°C; boiling point 444.6°C; specific gravity (rhombic) 2.07; (monoclinic) 1.957; valence 2, 4, 6.

2. See Periodic Table

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Etymology

Origin of sulfur

1300–50; Middle English sulphur < Latin sulpur, sulphur, sulfur brimstone, sulfur

Example Sentences

It is very heavy, thick, dark and high in sulfur, often called a sour oil.

From BBC • Apr. 7, 2026

The government on March 12 agreed to allow higher sulfur levels in petrol for 60 days.

From The Wall Street Journal • Mar. 31, 2026

Gulf states produce key minerals used in fertilizer production, including urea, phosphate, ammonia, and sulfur.

From Barron's • Mar. 29, 2026

The fighting has stranded big chunks of the world’s supply of ammonia, urea, sulfur and phosphates.

From The Wall Street Journal • Mar. 28, 2026

I fetch one now, strike it against the box, and let Mrs. Janssen’s penciled sleuthing burn into sulfur and ash.

From "Girl in the Blue Coat" by Monica Hesse