jumbo

UK: /ˈdʒʌmbəʊ/ US: /ˈdʒʌmboʊ/ ,( jum′bō)

Inflections of 'jumbo' (n): npl: jumbos

WordReference Random House Learner's Dictionary of American English © 2026

jum•bo /ˈdʒʌmboʊ/   n., pl. -bos, adj. 
n. [countable]

1. Informal Terms one that is very large of its kind, as a very large jet airplane.

adj. [usually: before a noun]

2. Informal Terms very large:
   a jumbo box of cereal.

WordReference Random House Unabridged Dictionary of American English © 2026

jum•bo  ( jum′bō), n., pl. -bos, adj. 

[Informal.]

n. 

1. Informal Terms a very large person, animal, or thing.
2. Informal Terms, Aeronautics See jumbo jet. 
3. Informal Terms, Nautical U.S. Naut.
   • a forestaysail having a boom (jum′bo boom′) along its foot, used esp. on schooners.
   • a sail used in place of a course on a square-rigged ship, having the form of an isosceles triangle set apex downward.
   • a narrow triangular sail set point downward in place of a foresail on a topsail schooner.

adj. 

4. Informal Terms very large:
   the jumbo box of cereal.

• 1800–10; origin, originally uncertain; popularized as the name of a large elephant purchased and exhibited by P.T. Barnum in 1882

Collins Concise English Dictionary © HarperCollins Publishers::

jumbo / ˈdʒʌmbəʊ/ noun ( -bos)

1. a very large person or thing
2. (as modifier): a jumbo box of detergent
3. See jumbo jet

Etymology: 19th Century: after the name of a famous elephant exhibited by P. T. Barnum, from Swahili jumbe chief