In art, primary colors are the ones that cannot be achieved by mixing pigments – and by mixing which we get all the other colors, called complementary, secondary, and tertiary. Physics uses the term differently.

In a measuring system, base units are the fundamental units of mass, length, time, or electric current.

Unlike complex concepts (which aren't necessarily complicated), basic concepts are the ones that often (or always) defy definition and are exhausted by pointing out their examples.

To answer the question, "What is physics?" the easiest honest answer would be to point to one of the great physical theories (such as Newton's laws, Maxwell's field theory, Einstein's relativity, or quantum mechanics).

Pointing at a democratic society would be the best way to answer the question, "What is a democratic society?"

Naturally, the list of definition-defying concepts would include the three major ones: love, hope, and faith.

According to some experts, boredom is defined in Ecclesiastes as "vexation of spirit." Very well. But what is vexation of spirit? Please don't say "boredom."

What is a number? It is not a numeral: a numeral is a drawn symbol denoting a number. What is a number?

And so forth.

Is there a term for these ... basic ... elementary ... base ... rudimentary ... primary ... fundamental ... primordial ... concepts?

  • 1
    "Fundamental ... concepts..." fundamentals?
    – Laurel
    May 20 at 1:08
  • 1
    Complimentary colors are My, what a lovely green dress you have! It goes wonderfully with your complexion!, whereas complementary colors are That magenta scarf clashes just terribly with that green dress you have!
    – tchrist
    May 20 at 1:13
  • 2
    @tchrist: Thank you, I stand corrected.
    – Ricky
    May 20 at 1:57
  • 1
    @tchrist: When I began reading your comment, saw "complimentary colors", and glanced at your name, I was shocked. But only for a split second, because I knew that what I had thought could not be true; and, indeed, as I continued reading, the fifth word of the first example shewed that it was not. May 20 at 2:07
  • 1
    I don’t know the word, but I imagine it would be the love child of the human condition and primitive notion. May 20 at 2:39


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