supplement

noun

1. Something added; especially, such an addition added to make up for a deficiency.

   “Near-synonyms: see Thesaurus:adjunct”

   “Athletes' use of herbal supplements has skyrocketed in the past two decades. At the top of the list of popular herbs are echinacea and ginseng, whereas garlic, St. John's wort, soybean, ephedra and others are also surging in popularity or have been historically prevalent.”

   “AI models will not completely replace the humans, she said, but will serve as a “supplement” intended to aid in the brand’s representation of various sizes, skin tones and ages.”

2. An extension to a document or publication that adds information, corrects errors, or brings up to date.
3. An additional section of a newspaper devoted to a specific subject; an additional section of a journal issue, or an additional issue, for a similar purpose.

   “the literary supplement”

   “"Mid-Lent, and the Enemy grins," remarked Selwyn as he started for church with Nina and the children. Austin, knee-deep in a dozen Sunday supplements, refused to stir; poor little Eileen was now convalescent from grippe, but still unsteady on her legs; her maid had taken the grippe, and now moaned all day: "Mon dieu! Mon dieu! Che fais mourir!"”

4. An angle that, when added to a given angle, makes 180°; a supplementary angle.
5. A vitamin, herbal extract, or chemical compound ingested to meet dietary deficiencies or enhance muscular development; the dosage form that conveys or embodies it (e.g., tablet, capsule, pill, powder, beverage).

   “Vitamins, minerals, and essential fatty acids must come from either the diet or supplements.”

   “Menstruators are likelier to need an iron supplement than non-menstruators, whose diet alone is usually sufficient.”

   “She wasn't getting enough iron, so they prescribed a supplement.”

6. A surcharge, additional cost, especially for food in a restaurant.

   “There is a £2 supplement if you choose the steak.”

7. An adjunct that is nonessential, especially a supplementary relative clause.

verb

1. To provide or make a supplement to something.

   “I supplement my income by working as a model.”

   “Using the countless tons of rock from the cliff-face, supplemented by much more from inland, they threw out a huge breakwater, 2,000 ft. long and 80 ft. high, roughly at right angles to the quay, so forming an almost completely sheltered corner. Fifty years later, this massive mole is still standing up to the worst that the Irish Sea can do.”