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