The Collaborative International Dictionary of English v.0.48:

Research \Re*search"\ (r?-s?rch"), n. [Pref. re- + search: cf
   OF. recerche, F. recherche.]
   1. Diligent inquiry or examination in seeking facts or
      principles; laborious or continued search after truth; as,
      researches of human wisdom; to research a topic in the
      library; medical research.
      [1913 Webster]

            The dearest interests of parties have frequently
            been staked on the results of the researches of
            antiquaries.                          --Macaulay.
      [1913 Webster]

   2. Systematic observation of phenomena for the purpose of
      learning new facts or testing the application of theories
      to known facts; -- also called scientific research. This
      is the research part of the phrase "research and
      development" (R&D).

   Note: The distinctive characteristic of scientific research
         is the maintenance of records and careful control or
         observation of conditions under which the phenomena are
         studied so that others will be able to reproduce the
         observations. When the person conducting the research
         varies the conditions beforehand in order to test
         directly the effects of changing conditions on the
         results of the observation, such investigation is
         called experimental research or experimentation or
         experimental science; it is often conducted in a
         laboratory. If the investigation is conducted with a
         view to obtaining information directly useful in
         producing objects with commercial or practical utility,
         the research is called applied research.
         Investigation conducted for the primary purpose of
         discovering new facts about natural phenomena, or to
         elaborate or test theories about natural phenomena, is
         called basic research or fundamental research.
         Research in fields such as astronomy, in which the
         phenomena to be observed cannot be controlled by the
         experimenter, is called observational research.
         Epidemiological research is a type of observational
         research in which the researcher applies statistical
         methods to analyse patterns of occurrence of disease
         and its association with other phenomena within a
         population, with a view to understanding the origins or
         mode of transmission of the disease.
         [PJC]

   Syn: Investigation; examination; inquiry; scrutiny.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Experimentation \Ex*per`i*men*ta"tion\, n.
   The act of experimenting; practice by experiment. --J. S.
   Mill.
   [1913 Webster]

WordNet (r) 3.0 (2006):

experimentation
    n 1: the testing of an idea; "it was an experiment in living";
         "not all experimentation is done in laboratories" [syn:
         experiment, experimentation]
    2: the act of conducting a controlled test or investigation
       [syn: experiment, experimentation]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "experimentation":
   R and D, control, control experiment, controlled experiment,
   cut and try, empiricism, experiment, experimental design,
   experimental method, experimental proof, experimentalism,
   hit and miss, noble experiment, pragmatism,
   research and development, rule of thumb, tentative method,
   tentativeness, test, testing, trial, trial and error, trial run,
   trying