bolus

noun

bo·​lus ˈbō-ləs 

plural boluses

1

: a rounded mass: such as

a

: a large pill

b

: a soft mass of chewed food

2

medical

a

: a dose of a substance (such as a drug) given intravenously

b

: a large dose of a substance given by injection for the purpose of rapidly achieving the needed therapeutic concentration in the bloodstream

Examples of bolus in a Sentence

Recent Examples on the Web

Unlike the older standard of care, which requires a 60-minute infusion, TNKase can be administered in a single five-second bolus. — Time Contributors, Time, 27 Apr. 2026

There, he was prescribed brimhana, or tissue regeneration, using a bolus therapy made from goat meat mixed with rice, milk, and spices. — Mark Ellwood, Robb Report, 14 Feb. 2026

Mazlish watched as his wife programmed her insulin pump to deliver both dribbles of basal insulin throughout the day and a large bolus with meals. — Carrie Arnold, Scientific American, 14 Oct. 2025

Unlike human pesticides, though, termite boluses were not lethal to the weed. — ArsTechnica, 10 Oct. 2025

Word History

Etymology

Late Latin, from Greek bōlos lump

First Known Use

1562, in the meaning defined at sense 1

Phrases Containing bolus

• holus-bolus

Rhymes for bolus

• colas
• polis
• solus
• embolus
• gladiolus
• nucleolus

Medical Definition

bolus

noun

bo·​lus ˈbō-ləs 

plural boluses

1

: a rounded mass: as

a

: a large pill

b

: a soft mass of chewed food

2

a

: a dose of a substance (as a drug) given intravenously

b

: a large dose of a substance given by injection for the purpose of rapidly achieving the needed therapeutic concentration in the bloodstream

the patient receives a bolus dose to reach the minimum effective analgesic concentration

—J. F. Camp

subcutaneous injection of a premeal bolus of fast-acting insulin