The Collaborative International Dictionary of English v.0.48:

Annular \An"nu*lar\, a. [L. annularis, fr. annulis ring: cf. F.
   annulaire.]
   1. Pertaining to, or having the form of, a ring; forming a
      ring; ringed; ring-shaped; as, annular fibers.
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   2. Banded or marked with circles.
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   Annular eclipse (Astron.), an eclipse of the sun in which
      the moon at the middle of the eclipse conceals the central
      part of the sun's disk, leaving a complete ring of light
      around the border.
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The Collaborative International Dictionary of English v.0.48:

Eclipse \E*clipse"\ ([-e]*kl[i^]ps"), n. [F. ['e]clipse, L.
   eclipsis, fr. Gr. 'e`kleipsis, prop., a forsaking, failing,
   fr. 'eklei`pein to leave out, forsake; 'ek out + lei`pein to
   leave. See Ex-, and Loan.]
   1. (Astron.) An interception or obscuration of the light of
      the sun, moon, or other luminous body, by the intervention
      of some other body, either between it and the eye, or
      between the luminous body and that illuminated by it. A
      lunar eclipse is caused by the moon passing through the
      earth's shadow; a solar eclipse, by the moon coming
      between the sun and the observer. A satellite is eclipsed
      by entering the shadow of its primary. The obscuration of
      a planet or star by the moon or a planet, though of the
      nature of an eclipse, is called an occultation. The
      eclipse of a small portion of the sun by Mercury or Venus
      is called a transit of the planet.
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   Note: In ancient times, eclipses were, and among
         unenlightened people they still are, superstitiously
         regarded as forerunners of evil fortune, a sentiment of
         which occasional use is made in literature.
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               That fatal and perfidious bark,
               Built in the eclipse, and rigged with curses
               dark.                              --Milton.
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   2. The loss, usually temporary or partial, of light,
      brilliancy, luster, honor, consciousness, etc.;
      obscuration; gloom; darkness.
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            All the posterity of our fist parents suffered a
            perpetual eclipse of spiritual life.  --Sir W.
                                                  Raleigh.
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            As in the soft and sweet eclipse,
            When soul meets soul on lovers' lips. --Shelley.
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   Annular eclipse. (Astron.) See under Annular.

   Cycle of eclipses. See under Cycle.
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WordNet (r) 3.0 (2006):

annular eclipse
    n 1: only a thin outer disk of the sun can be seen