from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Needed or required: synonym: indispensable.
  • adjective Unavoidably determined by prior conditions or circumstances; inevitable.
  • adjective Logically inevitable.
  • adjective Required by obligation, compulsion, or convention.
  • noun Something indispensable.

from The Century Dictionary.

  • Such as must be; that cannot be otherwise.
  • Such that it cannot be disregarded or omitted; indispensable; requisite; essential; needful; required: as, air is necessary to support animal life; food is necessary to nourish the body.
  • In law:
  • Requisite for reasonable convenience and facility or completeness in accomplishing the purpose intended: as, the land necessary for building a railroad.
  • Naturally and inseparably connected in the ordinary course: as, necessary consequences.
  • Acting from compulsion or the absolute determination of causes: opposed to free. See free.
  • Synonyms Necessary, Essential, Requisite, Needful. The following remarks refer to the application of the words to ordinary practical affairs, not to philosophy. Necessary is so general a word that it covers all the others, and has the additional sense, which they do not have, of inevitable. Essential is an absolute word, noting that which is a part of the chief end of the action, or of every mode of bringing that end about. Requisite is less strong than essential, and needful is less strong still; yet each is strong and emphatic, applying to that which is imperatively needed. Needful generally applies to concrete, and often to temporary, things: as, knowledge of the countries visited is requisite, and even essential, to enjoyment of travel, but money is needful in order to be able to travel at all. Needful is often applied to that which must be supplied to produce or effect a perfect state or action.
  • noun Anything that is necessary or indispensable; that which cannot be disregarded or omitted: as, the necessaries of life.
  • noun A privy; a water-closet.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective Such as must be; impossible to be otherwise; not to be avoided; inevitable.
  • adjective Impossible to be otherwise, or to be dispensed with, without preventing the attainment of a desired result; indispensable; requisite; essential.
  • adjective Acting from necessity or compulsion; involuntary; -- opposed to free.
  • noun A thing that is necessary or indispensable to some purpose; something that one can not do without; a requisite; an essential; -- used chiefly in the plural.
  • noun A privy; a water-closet.
  • noun (Law) Such things, in respect to infants, lunatics, and married women, as are requisite for support suitable to station.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • adjective needed, required
  • noun archaic, UK bathroom, toilet, loo

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun anything indispensable
  • adjective unavoidably determined by prior circumstances
  • adjective absolutely essential


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English necessarie, from Old French necessaire, from Latin necessārius, from necesse; see ked- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English necessarye, from Old French necessaire, from Latin necessārius ("unavoidable, inevitable, indispensable, requisite"), from necesse ("unavoidable, inevitable, indispensable"), neuter adjective with esse and habeō ("I have"), probably originating from ne cessum or non cessum, from ne ("not") + cessus, perfect passive participle of cēdō ("I yield"); see cede.


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  • Prayer as the highest that can be lived on earth, telling Martha that activity, even in the most necessary duties, was not after all the best use to which time and love could be put, but rather that _Mary had chosen the best part ... the one thing that is necessary_, and that it

    Paradoxes of Catholicism Robert Hugh Benson 1892

  • It is not necessary absolutely that any man should continue to live; but it is necessary _morally_ that, if he would continue to live, he should eat and sleep, food and rest being, according to the established constitution of Nature, a _necessary condition_ or indispensable means for the support of life.

    Modern Atheism under its forms of Pantheism, Materialism, Secularism, Development, and Natural Laws James Buchanan 1837

  • She kept telling me that I could have it (the necessary procedure) done as an in-patient procedure and then I could just be sterilized "while we're in there" at the same time, and it wouldn't hurt (as opposed to having the * necessary* procedure done in-office that she assured me would really hurt).

    Alex Jones' Prison 2009

  • It is, we think, impossible to compare the sentence which prohibits a State from laying “imposts, or duties on imports or exports, except what may be absolutely necessary for executing its inspection laws, ” with that which authorizes Congress “to make all laws which shall be necessary and proper for carrying into execution” the powers of the general government, without feeling a conviction that the convention understood itself to change materially the meaning of the word “necessary, ” by prefixing the word “absolutely.

    Opinion of Chief Justice Marshall, in the Case of McCulloch vs. the State of Maryland 1909

  • And yet, as it was necessary to appoint a certain day, in order that the people might know when they should assemble, the _Christian church_, (not the apostles,) has up appointed Sunday (the Lord's day) for this purpose; and to this change she was the more inclined and willing, that the people might have an example of Christian _liberty_, and might know that _the observance of neither the Sabbath nor any other day is necessary_.

    American Lutheranism Vindicated; or, Examination of the Lutheran Symbols, on Certain Disputed Topics Including a Reply to the Plea of Rev. W. J. Mann 1836

  • "Well," went on the other nervously, "I want you to speak for me, if necessary -- _if necessary_, you understand?

    Dawn of All Robert Hugh Benson 1892

  • And I use the term necessary because this generation has a very narrow definition of necessary.

    If they won’t pay for Facebook, they won’t pay for your city hall reporter » Nieman Journalism Lab 2009

  • The term necessary being can be understood in different ways.

    Cosmological Argument Reichenbach, Bruce 2008

  • For the one part contends that the term necessary should not be used concerning the new obedience, for that this flows not from any necessity or constraint, but from a voluntary spirit.

    The Creeds of the Evangelical Protestant Churches. 1889

  • But the other part judges that the term necessary should by all means be retained, inasmuch as this obedience is not left to our mere will, and therefore is not free, but that regenerate men are bound to render such service.

    The Creeds of the Evangelical Protestant Churches. 1889


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