ferrous

Etymology

It is formed from Latin ferrum (“iron”) with the suffix -ous,^{[2][3][4][5][6]} perhaps partly after French ferreux, which Cotgrave recorded once in 1611 for "as hard as iron" and which meant "containing iron" from 1752; the French chemical sense appears to be later than the English.^[2] Merriam-Webster Unabridged derives it from New Latin ferrosus,^[7] and Etymonline from Latin ferreus (“made of iron”).^[8] The Latin noun is of unknown origin, possibly Semitic through Etruscan,^[8] and is also the source of farrier.^[6][9]

Earliest recorded meaning

Containing iron, especially of metals and alloys: 1755, in Johnson's Dictionary, under eruginous.^[2] Merriam-Webster Unabridged also gives 1755,^[7] but Barnhart and Etymonline date the word to about 1865, and Dictionary.com to 1860–65.^[6][8][5]

Semantic evolution

The chemical sense, naming compounds in which iron has the lower valency, usually two, is recorded from 1832, in an American translation of Berzelius.^[2][7] It is contrasted with ferric, which Barnhart dates to 1799, in Humphry Davy.^[8][6] The general sense "containing iron" was at first, and is still often, found in the negative non-ferrous.^[3][2]

Timeline

• 1755 – containing iron, of or like iron.^[2][7] Barnhart and Etymonline date the word to about 1865.^[6][8]
• 1832 – chemistry, of compounds of iron in its lower valency, usually two.^[2]

Meanings

Adjective

1. Of, relating to or containing iron; of an alloy, containing more iron than any other metal: ferrous scrap.^[10][7][2]
2. (chemistry) Containing iron in the divalent state, as in ferrous sulfate.^[10][7][2]

Word family

• ferrous oxide
• ferrous sulfate
• ferrous sulfide

Related words

• ferric
• ferro-
• ferruginous
• farrier
• non-ferrous

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
4. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
5. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c d e Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
7. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
8. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
9. ^ Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
10. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins