The Collaborative International Dictionary of English v.0.48:

Particulate \Par*tic"u*late\ (p[aum]r*t[i^]k"[-u]*l[=a]t), v. t.
   & i. [See Particle.]
   To particularize. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Particulate \Par*tic"u*late\ (p[aum]r*t[i^]k"[-u]*l[asl]t), a.
   1. Having the form of a particle.
      [1913 Webster]

   2. Referring to, or produced by, particles, such as dust,
      minute germs, etc. [R.]
      [1913 Webster]

            The smallpox is a particulate disease. --Tyndall.
      [1913 Webster]

   3. Composed of particles; finely divided.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

particulate \par*tic"u*late\ (p[aum]r*t[i^]k"[-u]*l[asl]t), n.
   Matter composed of particles; -- often used in the pl.; as,
   the quantity of particulates in auto exhaust is strictly
   regulated.
   [PJC]

WordNet (r) 3.0 (2006):

particulate
    adj 1: composed of distinct particles [ant: nonparticulate]
    n 1: a small discrete mass of solid or liquid matter that
         remains individually dispersed in gas or liquid emissions
         (usually considered to be an atmospheric pollutant) [syn:
         particulate, particulate matter]