Source : Webster's Revised Unabridged Dictionary (1913)

Concrete \Con*crete"\, v. i. [imp. & p. p. {Concreted}; p. pr &
   vb. n. {Concreting}.]
   To unite or coalesce, as separate particles, into a mass or
   solid body.

   Note: Applied to some substances, it is equivalent to
         indurate; as, metallic matter concretes into a hard
         body; applied to others, it is equivalent to congeal,
         thicken, inspissate, coagulate, as in the concretion of
         blood. ``The blood of some who died of the plague could
         not be made to concrete.'' --Arbuthnot.