The Collaborative International Dictionary of English v.0.48:

Concrete \Con"crete\ (? or ?), a. [L. concretus, p. p. of
   concrescere to grow together; con- + crescere to grow; cf. F.
   concret. See Crescent.]
   1. United in growth; hence, formed by coalition of separate
      particles into one mass; united in a solid form.
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            The first concrete state, or consistent surface, of
            the chaos must be of the same figure as the last
            liquid state.                         --Bp. Burnet.
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   2. (Logic)
      (a) Standing for an object as it exists in nature,
          invested with all its qualities, as distinguished from
          standing for an attribute of an object; -- opposed to
          abstract. Hence:
      (b) Applied to a specific object; special; particular; --
          opposed to general. See Abstract, 3.
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                Concrete is opposed to abstract. The names of
                individuals are concrete, those of classes
                abstract.                         --J. S. Mill.
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                Concrete terms, while they express the quality,
                do also express, or imply, or refer to, some
                subject to which it belongs.      --I. Watts.
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   Concrete number, a number associated with, or applied to, a
      particular object, as three men, five days, etc., as
      distinguished from an abstract number, or one used without
      reference to a particular object.

   Concrete quantity, a physical object or a collection of
      such objects. --Davies & Peck.

   Concrete science, a physical science, one having as its
      subject of knowledge concrete things instead of abstract
      laws.

   Concrete sound or movement of the voice, one which slides
      continuously up or down, as distinguished from a
      discrete movement, in which the voice leaps at once from
      one line of pitch to another. --Rush.
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