What is "concrete quantity"

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.

   The first concrete state, or consistent surface, of the chaos must be of the same figure as the last liquid state.
   --Bp. Burnet.

2. (Logic)

   1. 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:

   2. Applied to a specific object; special; particular; -- opposed to general. See Abstract,

3. Concrete is opposed to abstract. The names of individuals are concrete, those of classes abstract.
   --J. S. Mill.

   Concrete terms, while they express the quality, do also express, or imply, or refer to, some subject to which it belongs.
   --I. Watts.

   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.