[1] : The Collaborative International Dictionary of English v.0.48

pollution \pollu"tion\, n. l. pollutio: cf. f. pollution.
   1. the act of polluting, or the state of being polluted in
      any sense of the verb; defilement; uncleanness; impurity.
      1913 webster

   2. med. the emission of semen, or sperm, at other times
      than in sexual intercourse. --dunglison.
      1913 webster

[2] : WordNet (r) 2.0

pollution
     n 1: undesirable state of the natural environment being
          contaminated with harmful substances as a consequence of
          human activities
     2: the state of being polluted syn: befoulment, defilement
     3: the act of contaminating or polluting; including either
        intentionally or accidentally unwanted substances or
        factors syn: contamination ant: decontamination
see also:
befoulment defilement contamination decontamination 

[3] : Moby Thesaurus II by Grady Ward, 1.0

101 moby thesaurus words for "pollution":
   abomination, abuse, abuse of office, adulteration, air, atrocity,
   bad, badness, bane, bastardizing, befouling, befoulment,
   besmirchment, blight, contamination, conversion,
   corrupt administration, corruption, crying evil, cutting, damage,
   debasement, defalcation, defilement, desecration, despoliation,
   destruction, detriment, dilution, dirtying, diversion, doctoring,
   embezzlement, envenoming, evil, festering, fortifying, fouling,
   grievance, harm, harmfulness, havoc, health hazard, hurt, ill,
   infection, injuriousness, injury, insalubriousness, insalubrity,
   lacing, maladministration, malfeasance, malpractice, malversation,
   menace to health, misapplication, misappropriation, mischief,
   misconduct, misemployment, misfeasance, mishandling, mismanagement,
   misusage, misuse, noise pollution, noisomeness, noxiousness,
   outrage, pathenogenicity, peculation, perversion, pilfering,
   poison, poisoning, poor stewardship, profanation, prostitution,
   ritual uncleanness, soiling, spiking, spoiling, staining, sullying,
   suppuration, tainting, the worst, toxin, unhealthfulness,
   unhealthiness, unsalutariness, unwholesomeness, venom, vexation,
   violation, vitiation, water, watering, woe, wrong

Pollution >> P Words
Pollution, definition of term: Pollution
pollution_pag1.html

Sound Pollution >> S Words
Sound Pollution, definition of term: Sound Pollution
sound+pollution_pag1.html

Air Pollution >> A Words
Air Pollution, definition of term: Air Pollution
air+pollution_pag1.html