adj

• (formal) Providing assistance or help; assistive, facilitative, helpful.
• (immunology) Enhancing the immune response to an antigen; also, containing a substance having such an effect.
• (medicine) Of a form of therapy or treatment: additional, supplementary; specifically (oncology), of a cancer treatment: given after removal of a primary tumour.
  "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— […]"

noun

• (formal) Someone or (more commonly) something that assists, facilitates, or helps; an aid, an assistant, a helper.
• (formal) Someone or (more commonly) something that assists, facilitates, or helps; an aid, an assistant, a helper.
  "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."
• (formal) Someone or (more commonly) something that assists, facilitates, or helps; an aid, an assistant, a helper.
• (formal) Someone or (more commonly) something that assists, facilitates, or helps; an aid, an assistant, a helper.