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rudimentary

American  
[roo-duh-men-tuh-ree, -tree] / ˌru dəˈmɛn tə ri, -tri /
Often rudimental

adjective

  1. pertaining to rudiments or first principles; elementary.

    a rudimentary knowledge of geometry.

    Synonyms:
    initial, fundamental
    Antonyms:
    advanced
  2. Biology. of the nature of a rudiment; undeveloped or vestigial.

    Synonyms:
    embryonic
    Antonyms:
    mature
  3. in an early, imperfect stage or form.

    How can we improve upon this admittedly rudimentary theory?


rudimentary British  
/ ˌruːdɪˈmɛntərɪ /

adjective

  1. basic; fundamental; not elaborated or perfected

  2. incompletely developed; vestigial

    rudimentary leaves

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

See elementary.

Other Word Forms

Etymology

Origin of rudimentary

First recorded in 1600–20; rudiment + -ary

Explanation

Rudimentary means basic, or at a very early stage. The test should be easy: it requires only a rudimentary understanding of the materials. The word rude means simple or offensive — and people with only rudimentary understanding of good manners might not know how that belching is rude. If you remember that the word rude is the foundation of rudimentary, you'll have a rudimentary understanding of the word.

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Vocabulary lists containing rudimentary

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

By spring 2025, the team had a rudimentary product to identify users pursuing biological weapons.

From The Wall Street Journal Jul. 26, 2026

He would steal ad posters, paint over them with rudimentary cartoon skulls with X’ed-out eyes in pastel colors, then carefully replace them.

From Los Angeles Times Jul. 8, 2026

Around a dozen are close to completion while others sit with the logos of the shipping companies still visible on the outside, rudimentary windows cut out of the sides.

From BBC May 22, 2026

The fishermen, who live in rudimentary wooden houses on stilts, say they now earn no more than $10 to $20 a week from catches, compared to $100 a decade ago.

From Barron's May 20, 2026

The diagrams that originally accompanied Vitruvius’s text were in any case evidently few in number and extremely rudimentary.

From "The Invention of Science" by David Wootton

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