I read from the free dictionary that the three words "rudiment", "fundamental", and "foundation" are listed as synonyms in thesaurus, with their individual meanings in regard to the learning of a discipline being

rudiment: a fundamental element, principle, or skill, as of a field of learning; the first principles or elementary stages of a subject.

fundamental: a basic principle, rule, law, or the like that serves as the groundwork of a system; essential part.

foundation: the basis or groundwork of anything.

Despite the definition of each word, I am still not quite sure whether these words can be used interchangeably or have some shades of meaning when they refer to the learning of a discipline. For example, do:

  • "I have acquired the rudiments of quantum mechanics."

  • "I have acquired the fundamentals of quantum mechanics."

  • "I have acquired the foundations of quantum mechanics."

sound the same or slightly differently? Does "rudiments" suggest less comprehensive knowledge, which may be anecdotal, of quantum mechanics than "fundamentals" and "foundations"? I make this speculation on the basis that "rudiment" also has other meanings:

a mere beginning, first slight appearance, or undeveloped or imperfect form of something


an organ or part in its earliest recognizable form, esp one in an embryonic or vestigial state.

That being so, is there any difference between "fundamentals" and "foundations" in this context? It's like the both suggest essential knowledge for having an adequate understanding of quantum mechanics.

  • careful with rudiments, it's not the best level: If one has learned the rudiments of sailing, it would be best not to venture out in a squall.
    – Lambie
    Apr 13, 2018 at 20:12
  • @userr2684291 I don't know whether one or two colons should be put there if I want to follow with an illustration. Apr 20, 2018 at 22:41

1 Answer 1


A good way to check this is with an etymology dictionary. For example:

rudiment (n): 1540s, from Middle French rudiment (16c.) or directly from Latin rudimentum "early training, first experience, beginning, first principle," from rudis "unlearned, untrained" (see rude).

So rudimentary knowledge is something taught to someone who is completely unskilled. For example, a rudimentary carpentry skill might be how to hammer a nail in straight (without hitting your thumb), or how to glue together two pieces of wood.

Both "fundamental" and "foundation" share the same Latin root fundare ("to lay a bottom or foundation") so both words mean much the same thing. In contrast with rudiment, foundational/fundamental knowledge forms the basis for everything else in that field. Again, using carpentry as an example, this might be how to select good wood for a particular project, how to create proper joins, how to properly build load-bearing structures, how to use and maintain your tools, and so on.

Obviously there is some overlap between rudimentary and fundamental, since you need to teach the basics to someone untrained. But the intent is different -- it sounds much better to say you have a strong foundation in a discipline, rather than saying you have picked up the rudiments of that discipline.

  • Thank you for advising me to tell the shades of meaning among closely associated words by referring to their etymology. I had once got the advice somewhere on referring to a word's etymology to help with my memorization of its spelling (or rough speculation of the meaning of an unfamiliar word), but I found most web dictionaries seem not to provide clear information of etymology for most words, so I finally gave up resorting to etymology. However, I found most web dictionaries seem to have thesaurus, so I turn my recourse to thesaurus when I have difficulty clarifying the meaning of words. Apr 14, 2018 at 15:12
  • 1
    @CaptainBohemian Please see the link in my answer to the Online Etymology Dictionary, where you can look up almost any word. You do have to be careful since the meaning can shift over time, but etymology is a good way to find how various English words are related. Also be aware that some English words have Germanic roots via old Norse, others Latin roots (usually via Old French), and still others Germanic roots via Old Anglo-Saxon. Plus there are perhaps thousands of "borrowed" words from almost every other language on the planet. English is complicated.
    – Andrew
    Apr 14, 2018 at 15:25
  • Can you elaborate on "But the intent is different"? Do you mean "rudiment" refers to the knowledge of a dabbler, like nontechnical books of sciences for nonspecialists, whereas "fundamental" refers to the knowledge of a serious pursuer of the discipline, such as the university textbooks of quantum mechanics for a physics student? Thus "rudiment" refers to knowledge far shallower than "basics" does? So is it better to say that I've had the basics, rather than rudiments, of a discipline if I wish to emphasize my serious learning of it which, nonetheless, has not reached the foundational level? Apr 14, 2018 at 18:10
  • @CaptainBohemian Yes, more or less. Rudimentary refers to the basic skills or concepts of a field, that you would teach to someone who didn't know anything. Fundamental refers to the core skills or concepts, from which everything else in that field is built. Rudimentary skills are generally a simple subset of the fundamental skills. Someone who knows the rudimentary skills can be a serious student, just beginning their training. Eventually they'd be expected to learn all the fundamentals, and much more, to be considered a professional in that field.
    – Andrew
    Apr 14, 2018 at 21:41

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .