rudimentary

adjective

ru·​di·​men·​ta·​ry ˌrü-də-ˈmen-tə-rē 

-ˈmen-trē

1

: consisting in first principles : fundamental

had only a rudimentary formal education

—D. J. Boorstin

2

: of a primitive kind

the equipment of these past empire-builders was rudimentary

—A. J. Toynbee

3

: very imperfectly developed or represented only by a vestige

the rudimentary tail of a hyrax

rudimentarily

ˌrü-də-ˌmen-ˈter-ə-lē 

-ˈmen-trə-lē

adverb

rudimentariness

ˌrü-də-ˈmen-tə-rē-nəs 

-ˈmen-trē-

noun

Synonyms

• primitive

Examples of rudimentary in a Sentence

Because now, every schlemiel with a pair of mirrored sunglasses and a rudimentary grasp of the rules of poker thinks he can play cards with the pros. —A. J. Jacobs, New York Times Book Review, 8 May 2005

Despite the rudimentary nature of its instruments—an octant, a chronometer and a level—the Lewis and Clark Expedition was a triumph for science and natural history. —Daniel J. Boorstin, U.S. News & World Report, 11 July 1994

A few were hopeless imbeciles, unable to comprehend more than the rudimentary requirements of filling their bellies when food was placed before them … —Edgar Rice Burroughs, The Monster Men, 1929

This class requires a rudimentary knowledge of human anatomy.

When baseball was in its rudimentary stages, different teams played by different rules.

Some insects have only rudimentary wings.

Recent Examples on the Web

Without data centers, flights would be grounded (pilots could not get weather info and flight plans would not be available), communication would become rudimentary, payments would stop processing (welcome back, bartering) — even 911, which goes through an online system, would shut down. —Nick Lichtenberg, Fortune, 8 Oct. 2025

Over time, these rudimentary structures gave way to more ambitious designs. —Georgina Jedikovska, Interesting Engineering, 7 Oct. 2025

Photos shared with Newsweek by the San Diego Humane Society show several small dogs buried among the rubbish, having created a rudimentary tunnel system to move around their home. —Jack Beresford, MSNBC Newsweek, 7 Oct. 2025

Ants display rudimentary counting abilities, can understand the concept of zero and make tools. —Big Think, 25 Sep. 2025

Word History

Etymology

see rudiment

First Known Use

1619, in the meaning defined at sense 1

Rhymes for rudimentary

• alimentary
• complimentary
• documentary
• parliamentary
• sedimentary
• supplementary
• testamentary
• integumentary
• uncomplimentary
• unparliamentary
• interparliamentary
• metasedimentary

Kids Definition

rudimentary

adjective

ru·​di·​men·​ta·​ry ˌrüd-ə-ˈment-ə-rē 

-ˈmen-trē

1

: elementary sense 1, fundamental

2

: very imperfectly developed or represented only by a small part compared to the fully developed form

a rudimentary tail

Medical Definition

rudimentary

adjective

ru·​di·​men·​ta·​ry ˌrüd-ə-ˈment-ə-rē, -ˈmen-trē 

: very imperfectly developed or represented only by a vestige