adjuvant

English

WOTD – 19 August 2025

Etymology

Pandemrix, a vaccine for flu pandemics developed by GlaxoSmithKline. The larger ampoule with a purple cap contains an antigen solution, while the smaller one with a yellow cap contains an adjuvant (noun noun sense 1.2).

Learned borrowing from Latin adiuvant-, adjuvant- + English -ant (suffix forming adjectives with the sense ‘exhibiting a condition or process’; and forming agent nouns). Adiuvant-, adjuvant- are oblique stems of adiuvāns, adjuvāns (“assisting, helping”), the present active participle of adiuvō (“to assist, help; to be useful; etc.”), from ad- (“prefix meaning ‘to; toward’”) + iuvō (“to aid, help; to save”) (possibly from Proto-Indo-European *h₁ewH- (“to assist, help; to save”)).

Adjective adjective sense 3 (“of a form of therapy or treatment: additional, supplementary”) and noun noun sense 1.4 (“additive which aids or modifies the action of the principal ingredient of a drug”) are possibly derived from French adjuvant (adjective, noun).

Pronunciation

• (Received Pronunciation) IPA^(key): /ˈæd͡ʒʊv(ə)nt/
• (General American) enPR: 'ăj-ə-vənt, IPA^(key): /ˈæd͡ʒəv(ə)nt/

• Audio (General American):

  (file)

• Hyphenation: ad‧juv‧ant

Adjective

adjuvant (comparative more adjuvant, superlative most adjuvant)

1. (formal) Providing assistance or help; assistive, facilitative, helpful. [from 16th c.]

   Synonyms: assisting, auxiliary, complementary, contributory, helping, supporting

2. (immunology) Enhancing the immune response to an antigen; also, containing a substance having such an effect.
4. (medicine) Of a form of therapy or treatment: additional, supplementary; specifically (oncology), of a cancer treatment: given after removal of a primary tumour. [from 19th c.]
   • 2010, Siddhartha Mukherjee, “Halsted’s Ashes”, in The Emperor of all Maladies: A Biography of Cancer, New York, N.Y.: Scribner, →ISBN, page 219:

     Adjuvant chemotherapy, [Paul] Carbone conjectured, could be the surgeon's little helper. It would eradicate microscopic deposits of cancer left behind after surgery, thus extirpating any remnant reservoirs of malignancy in the body in early breast cancer— […]

Derived terms

• adjuvance
• adjuvancy
• adjuvanticity
• adjuvantly

Related terms

• adjutant
• aid
• aidance
• aidant
• aide

Translations

providing assistance or help — see also helpful

• Finnish: auttavainen (fi), avustava (fi), tuki- (fi)
• German: hilfreich (de), unterstützend (de)
• Spanish: adyuvante (es)

enhancing the immune response to an antigen; containing a substance having such an effect

• Finnish: adjuvanttinen
• French: please add this translation if you can

of a form of therapy or treatment: additional, supplementary; of a cancer treatment: given after removal of a primary tumour

• Finnish: adjuvanttinen
• French: adjuvant (fr)
• Italian: adiuvante, coadiuvante (it)
• Portuguese: adjuvante
• Spanish: adyuvante (es)

Noun

adjuvant (plural adjuvants)

1. (formal) Someone or (more commonly) something that assists, facilitates, or helps; an aid, an assistant, a helper. [from 16th c.]

   Synonyms: accessory, attendant

   2. (agriculture) An additive (often a separate product) that enhances the efficacy of a pesticide, but has little or no pesticidal effect itself. [from mid 20th c.]
   4. (immunology) A substance enhancing the immune response to an antigen. [from 20th c.]
      • 1914 November, Frederick P. Gay, Edith J[ane] Claypole, “Specific Hyperleukocytosis: Studies in Typhoid Immunization”, in Archives of Internal Medicine‎^[1], volume XIV, number 5, →DOI, →ISSN, →OCLC, pages 662–670:

        The well-known tropic action of immune serum as an adjuvant to phagocytosis suggested early in our studies that we might here be dealing with a similar phenomenon.

   5. (medicine) A form of therapy or treatment which is additional or supplementary to another, or which enhances the effectiveness of another. [from 18th c.]
   7. (pharmacology, archaic) An additive which aids or modifies the action of the principal ingredient of a drug. [from 19th c.]

Derived terms

• adjuvanted (adjective)
• adjuvant therapy
• chemoadjuvant
• coadjuvant
• Freund's adjuvant
• immunoadjuvant
• neoadjuvant
• postneoadjuvant

Translations

someone or something that assists, facilitates, or helps

• Finnish: adjutantti (fi), apumies (fi), apuri (fi), assistentti (fi), avustaja (fi)

additive that enhances the efficacy of a pesticide, but has little or no pesticidal effect itself

• Finnish: liitännäisaine
• Polish: adiuwant m
• Swedish: adjuvant c

substance enhancing the immune response to an antigen

• Czech: adjuvans (cs) n
• Finnish: adjuvantti (fi)
• Welsh: adgynorthwyydd m

form of therapy or treatment which is additional or supplementary to another, or which enhances the effectiveness of another

• Finnish: adjuvantti (fi)
• French: please add this translation if you can

additive which aids or modifies the action of the principal ingredient of a drug

• Czech: adjuvans (cs) n
• Finnish: adjuvantti (fi)
• Welsh: adgynorthwyydd m

Further reading

• adjuvant therapy on Wikipedia.Wikipedia
• immunologic adjuvant on Wikipedia.Wikipedia
• adjuvant (disambiguation) on Wikipedia.Wikipedia
• William Dwight Whitney, Benjamin E[li] Smith, editors (1911), “adjuvant”, in The Century Dictionary […], New York, N.Y.: The Century Co., →OCLC.
• “adjuvant”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.
• “adjuvant”, in OneLook Dictionary Search.

French

Pronunciation

• IPA^(key): /a.dʒy.vɑ̃/

• Audio (France (Brétigny-sur-Orge)):

  (file)

• Audio (France):

  (file)

• Audio (France (Lyon)):

  (file)

Adjective

adjuvant (feminine adjuvante, masculine plural adjuvants, feminine plural adjuvantes)

1. adjuvant

Noun

adjuvant m (plural adjuvants)

1. adjuvant

Further reading

• “adjuvant”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012

Latin

Verb

adjuvant

1. third-person plural present active indicative of adjuvō

Romanian

Etymology

Borrowed from French adjuvant or German Adjuvant.

Adjective

adjuvant m or n (feminine singular adjuvantă, masculine plural adjuvanți, feminine/neuter plural adjuvante)

1. adjuvant

Declension

Declension of adjuvant

		singular				plural
		masculine	neuter	feminine		masculine	neuter	feminine
nominative- accusative	indefinite	adjuvant		adjuvantă		adjuvanți	adjuvante
	definite	adjuvantul		adjuvanta		adjuvanții	adjuvantele
genitive- dative	indefinite	adjuvant		adjuvante		adjuvanți	adjuvante
	definite	adjuvantului		adjuvantei		adjuvanților	adjuvantelor

Noun

adjuvant m (plural adjuvanți)

1. adjuvant

Declension

	singular			plural
	indefinite	definite		indefinite	definite
nominative-accusative	adjuvant	adjuvantul		adjuvanți	adjuvanții
genitive-dative	adjuvant	adjuvantului		adjuvanți	adjuvanților
vocative	adjuvantule			adjuvanților