Sulfur is the pale yellow, strong-smelling chemical element used in matches, gunpowder and pest control. Sulphur, capitalised, is a place name given to several towns, including Sulphur, Louisiana and Sulphur, Oklahoma. A memory hook: sulfur is the substance, Sulphur is the town.
The core difference
Sulfur is a chemical element; Sulphur is a place name used for towns in the United States.
- sulfur — the pale yellow chemical element, or its yellowish-green colour: The volcanic vents released a strong smell of sulfur.
- Sulphur — a place name used for towns such as Sulphur, Louisiana and Sulphur, Oklahoma: The town of Sulphur was named for its mineral springs.
How to tell them apart
Sulfur as a word for the element traces back through Middle English sulphur, from Latin sulpur/sulfur of uncertain origin, and it replaced the older Old English word swefl. The towns named Sulphur took their name from nearby mineral springs, where the mineral gave the settlements their identity.
The mix-up mostly comes up when a reader sees the capitalised place name Sulphur and assumes it must be a spelling of the element's name, or vice versa. Checking whether the word is naming a substance or a place is the quickest way to tell which one is meant.
