deficiency

Etymology

It is borrowed from Late Latin dēficientia (“a lack, want”),^[2][3][4][5] from dēficiēns, the present participle of dēficiō (“to fail, be lacking; to desert, revolt”),^[2][4][6] which is formed from dē- (“down, away”) and faciō (“to do, make”),^[2][6] from Proto-Indo-European *dhe- (“to set, put”).^[2] The OED instead treats it as formed within English, like deficit, with the suffix -ency,^[6] and the Shorter Oxford derives it from the adjective deficient.^[7] The older English form, now rare or obsolete, was deficience, from the mid-15th century;^[2] Johnson (1755) entered both forms.^[8]

Earliest recorded meaning

The quality or state of being deficient: Merriam-Webster dates this sense to 1603,^[4] the OED to 1634, in M. Wilson's Mercy and Truth.^[6][9] Etymonline gives the 1630s for "state of falling short, a lack or failing".^[2]

Semantic evolution

From the 1660s the word also meant a particular thing that is lacking, a defect or imperfection, used with a and in the plural.^[2][6][9] Johnson (1755) defined it as "defect; failing; imperfection" and quoted Milton's "Is no deficience found".^[8] A financial sense, the amount by which revenue falls short of expenditure, is recorded from 1719, giving deficiency bill and deficiency act.^[6][9] Smyth's Sailor's Word-Book (1867) records the word for what is missing from a ship's cargo at delivery.^[10] Technical senses followed in mathematics, for the deficiency of a curve (1865), and in genetics, for the loss of part of a chromosome (1916).^[6] The modern sense of a lack of something needed for health, such as a vitamin, is the one the American dictionaries give as an example of a shortage,^[11][12] and the Shorter Oxford records mental deficiency for the condition of having a mental handicap.^[7]

Timeline

• 1603 – the quality or state of being deficient (Merriam-Webster's date).^[4]
• 1634 – the same sense, the OED's first record.^[6][9]
• 1664 – an instance of this; a defect, an imperfection.^[6][9]
• 1719 – the amount by which revenue falls short of expenditure.^[6][9]
• 1755 – Johnson defines it as defect, failing, imperfection.^[8]
• 1865 – in mathematics, the deficiency of a curve.^[6]
• 1916 – in genetics, the deletion of part of a chromosome.^[6]

Meanings

Noun

1. The state of lacking something or of being inadequate or incomplete: the deficiency of the evidence.^[11][13][4]
2. A shortage of something, especially of a substance needed for health: an iron deficiency.^[11][12][4]
3. A particular lack or defect; a failing: She made up for the deficiencies of the old plan.^[6][7]
4. A deficit; the amount by which something falls short.^[13][6]
5. (genetics) The absence of a gene or of part of a chromosome; a deletion.^[13][4][6]
6. (mathematics) The number by which a curve's double points fall short of the greatest number possible for a curve of the same degree.^[6][1]

Word family

• immunodeficiency
• acquired immune deficiency syndrome
• deficiency disease

Related words

• deficient
• deficit
• deficience

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
4. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c d e f g h i j k l m n o p Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
7. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
8. ^ a b c Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
9. ^ a b c d e f Kay, Christian; Roberts, Jane; Samuels, Michael; Wotherspoon, Irené, eds. (2009), Historical Thesaurus of the Oxford English Dictionary, Oxford: Oxford University Press; online edition (2024)
10. ^ Smyth, W. H. (1867), The Sailor's Word-Book: An Alphabetical Digest of Nautical Terms, London: Blackie and Son
11. ^ a b c The American Heritage Dictionary of the English Language (1992), 3rd ed., Boston: Houghton Mifflin
12. ^ a b Merriam-Webster's Collegiate Dictionary (2003), 11th ed., Springfield, Mass.: Merriam-Webster
13. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins