berlin blue
Preserved but no longer current.
Meaning · English
It is hydrated ferric ferrocyanide, and prussic acid (hydrocyanic acid) is made from it.
Era: ca. 1898 (Victorian)
Sources & notes
Reproduced from Brewer’s Dictionary of Phrase and Fable (1898 edition, public domain; archive.org, retrieved 2026-07-31; OCR text, minor errors possible). Reflects the scholarship and attitudes of its era.
Common questions
What does “berlin blue” mean?
It is hydrated ferric ferrocyanide, and prussic acid (hydrocyanic acid) is made from it.
Is “berlin blue” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.