1. [n]  any distinctive flag
2. [n]  an upright pole or beam (especially one used as a support); "distance was marked by standards every mile"; "lamps supported on standards provided illumination"
3. [n]  the ideal in terms of which something can be judged; "they live by the standards of their community"
4. [n]  a basis for comparison; a reference point against which other things can be evaluated; "they set the measure for all subsequent work"
5. [n]  the value behind the money in a monetary system
6. [n]  a board measure = 1980 board feet
7. [adj]  commonly used or supplied; "standard procedure"; "standard car equipment"
8. [adj]  regularly and widely used or sold; "a standard size"; "a stock item"
9. [adj]  established or widely recognized as a model of authority or excellence; "a standard reference work"
10. [adj]  conforming to or constituting a standard of measurement or value; or of the usual or regularized or accepted kind; "windows of standard width"; "standard sizes"; "the standard fixtures"; "standard brands"; "standard operating procedure"
11. [adj]  (linguistics) conforming to the established language usage of educated native speakers; "standard English" (American); "received standard English is sometimes called the King's English" (British)

Standard
Standard

more details ...

1. \Stand"ard\, n. [OF. estendart, F. ['e]tendard,
   probably fr. L. extendere to spread out, extend, but
   influenced by E. stand. See {Extend}.]
   1. A flag; colors; a banner; especially, a national or other
      ensign.
            His armies, in the following day, On those fair
            plains their standards proud display. --Fairfax.
   2. That which is established by authority as a rule for the
      measure of quantity, extent, value, or quality; esp., the
      original specimen weight or measure sanctioned by
      government, as the standard pound, gallon, or yard.
   3. That which is established as a rule or model by authority,
      custom, or general consent; criterion; test.
            The court, which used to be the standard of property
            and correctness of speech.            --Swift.
            A disposition to preserve, and an ability to
            improve, taken together, would be my standard of a
            statesman.                            --Burke.
   4. (Coinage) The proportion of weights of fine metal and
      alloy established by authority.
            By the present standard of the coinage, sixty-two
            shillings is coined out of one pound weight of
            silver.                               --Arbuthnot.
   5. (Hort.) A tree of natural size supported by its own stem,
      and not dwarfed by grafting on the stock of a smaller
      species nor trained upon a wall or trellis.
            In France part of their gardens is laid out for
            flowers, others for fruits; some standards, some
            against walls.                        --Sir W.
                                                  Temple.
   6. (Bot.) The upper petal or banner of a papilionaceous
      corolla.
   7. (Mech. & Carp.) An upright support, as one of the poles of
      a scaffold; any upright in framing.
   8. (Shipbuilding) An inverted knee timber placed upon the
      deck instead of beneath it, with its vertical branch
      turned upward from that which lies horizontally.
   9. The sheth of a plow.
   10. A large drinking cup. --Greene.
   {Standard bearer}, an officer of an army, company, or troop,
      who bears a standard; -- commonly called color sergeantor
      color bearer; hence, the leader of any organization; as,
      the standard bearer of a political party.
   

2. \Stand"ard\, a.
   1. Being, affording, or according with, a standard for
      comparison and judgment; as, standard time; standard
      weights and measures; a standard authority as to nautical
      terms; standard gold or silver.
   2. Hence: Having a recognized and permanent value; as,
      standard works in history; standard authors.
   3. (Hort.)
      (a) Not supported by, or fastened to, a wall; as, standard
          fruit trees.
      (b) Not of the dwarf kind; as, a standard pear tree.
   {Standard candle}, {Standard gauge}. See under {Candle}, and
      {Gauge}.
   {Standard solution}. (Chem.) See {Standardized solution},
      under {Solution}.
   

Standards are necessary for interworking, portability, and reusability. They may be de facto standards for various communities, or officially recognised national or international standards.

Andrew Tanenbaum, in his Computer Networks book, once said, "The nice thing about standards is that there are so many of them to choose from", a reference to the fact that competing standards become a source of confusion, division, obsolescence, and duplication of effort instead of an enhancement to the usefulness of products.

Some bodies concerned in one way or another with computing standards are IAB (RFC and STD), ISO, ANSI, DoD, ECMA, IEEE, IETF, OSF, W3C.