Roman alum

noun

: alum crystallized in cubes
especially : alum formerly made from alunite at Tolfa near Rome that was reddish because of a very small amount of iron oxide though otherwise very pure

Word History

First Known Use

1653, in the meaning defined above

Time Traveler
The first known use of Roman alum was in 1653

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Cite this Entry

“Roman alum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Roman%20alum. Accessed 31 Mar. 2023.

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