The Collaborative International Dictionary of English v.0.48:

Tax \Tax\, n. [F. taxe, fr. taxer to tax, L. taxare to touch,
   sharply, to feel, handle, to censure, value, estimate, fr.
   tangere, tactum, to touch. See Tangent, and cf. Task,
   Taste.]
   1. A charge, especially a pecuniary burden which is imposed
      by authority. Specifically:
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      (a) A charge or burden laid upon persons or property for
          the support of a government.
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                A farmer of taxes is, of all creditors,
                proverbially the most rapacious.  --Macaulay.
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      (b) Especially, the sum laid upon specific things, as upon
          polls, lands, houses, income, etc.; as, a land tax; a
          window tax; a tax on carriages, and the like.

   Note: Taxes are annual or perpetual, direct or
         indirect, etc.
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      (c) A sum imposed or levied upon the members of a society
          to defray its expenses.
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   2. A task exacted from one who is under control; a
      contribution or service, the rendering of which is imposed
      upon a subject.
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   3. A disagreeable or burdensome duty or charge; as, a heavy
      tax on time or health.
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   4. Charge; censure. [Obs.] --Clarendon.
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   5. A lesson to be learned; a task. [Obs.] --Johnson.
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   Tax cart, a spring cart subject to a low tax. [Eng.]
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   Syn: Impost; tribute; contribution; duty; toll; rate;
        assessment; exaction; custom; demand.
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The Collaborative International Dictionary of English v.0.48:

Annual \An"nu*al\, n.
   1. A thing happening or returning yearly; esp. a literary
      work published once a year.
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   2. Anything, especially a plant, that lasts but one year or
      season; an annual plant.
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            Oaths . . . in some sense almost annuals; . . . and
            I myself can remember about forty different sets.
                                                  --Swift.
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   3. (R. C. Ch.) A Mass for a deceased person or for some
      special object, said daily for a year or on the
      anniversary day.
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The Collaborative International Dictionary of English v.0.48:

Annual \An"nu*al\ (?; 135), a. [OE. annuel, F. annuel, fr. L.
   annualis, fr. annus year. Cf. Annals.]
   1. Of or pertaining to a year; returning every year; coming
      or happening once in the year; yearly.
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            The annual overflowing of the river [Nile]. --Ray.
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   2. Performed or accomplished in a year; reckoned by the year;
      as, the annual motion of the earth.
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            A thousand pound a year, annual support. --Shak.
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   2. Lasting or continuing only one year or one growing season;
      requiring to be renewed every year; as, an annual plant;
      annual tickets. --Bacon.
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WordNet (r) 3.0 (2006):

annual
    adj 1: completing its life cycle within a year; "a border of
           annual flowering plants" [syn: annual, one-year]
           [ant: biennial, perennial, two-year]
    2: occurring or payable every year; "an annual trip to Paris";
       "yearly medical examinations"; "annual (or yearly) income"
       [syn: annual, yearly]
    n 1: (botany) a plant that completes its entire life cycle
         within the space of a year
    2: a reference book that is published regularly once every year
       [syn: annual, yearly, yearbook]