heterocyclic

from WordNet (r) 3.0 (2006)
heterocyclic
    adj 1: containing a closed ring of atoms of which at least one
           is not a carbon atom
    n 1: a compound containing a heterocyclic ring [syn:
         {heterocyclic compound}, {heterocyclic}, {heterocycle}]
    
from The Collaborative International Dictionary of English v.0.48
Cyclic \Cyc"lic\ (s?k"l?k or s?"kl?k), Cyclical \Cyc"lic*al\
   (s?k"l?-kal), a. [Cf. F. cycluque, Gr. kykliko`s, fr. ky`klos
   See {Cycle}.]
   1. Of or pertaining to a cycle or circle; moving in cycles;
      as, cyclical time. --Coleridge.
      [1913 Webster]

   2. (Chemistry) Having atoms bonded to form a ring structure.
      Opposite of {acyclic}.

   Note: Used most commonly in respect to organic compounds.

   Note: [Narrower terms: {bicyclic}; {heterocyclic};
         {homocyclic, isocyclic}]

   Syn: closed-chain, closed-ring.
        [WordNet 1.5]

   3. Recurring in cycles[2]; having a pattern that repeats at
      approximately equal intervals; periodic. Opposite of
      {noncyclic}.

   Note: [Narrower terms: {alternate(prenominal),
         alternating(prenominal)}; {alternate(prenominal), every
         other(prenominal), every second(prenominal)};
         {alternating(prenominal), oscillating(prenominal)};
         {biyearly}; {circadian exhibiting 24-hour
         periodicity)}; {circular}; {daily, diurnal};
         {fortnightly, biweekly}; {hourly}; {midweek,
         midweekly}; {seasonal}; {semestral, semestrial};
         {semiannual, biannual, biyearly}; {semiweekly,
         biweekly}; {weekly}; {annual, yearly}; {biennial};
         {bimonthly, bimestrial}; {half-hourly}; {half-yearly};
         {monthly}; {tertian, alternate(prenominal)};
         {triennial}]
         [WordNet 1.5]

   4. Marked by repeated cycles[2].
      [WordNet 1.5]

   {Cyclic chorus}, the chorus which performed the songs and
      dances of the dithyrambic odes at Athens, dancing round
      the altar of Bacchus in a circle.

   {Cyclic poets}, certain epic poets who followed Homer, and
      wrote merely on the Trojan war and its heroes; -- so
      called because keeping within the circle of a single
      subject. Also, any series or coterie of poets writing on
      one subject. --Milman.
      [1913 Webster]
    

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