The Collaborative International Dictionary of English v.0.48:

Scientist \Sci"en*tist\, n.
   One learned in science; a scientific investigator; one
   devoted to scientific study; a savant. [Recent]
   [1913 Webster]

   Note: Twenty years ago I ventured to propose one [a name for
         the class of men who give their lives to scientific
         study] which has been slowly finding its way to general
         adoption; and the word scientist, though scarcely
         euphonious, has gradually assumed its place in our
         vocabulary. --B. A. Gould (Address, 1869).
         [1913 Webster] Sci-Fi

The Collaborative International Dictionary of English v.0.48:

Researcher \Re*search"er\ (-[~e]r), n.
   One who conducts research. In the field of scientific
   research, also called an investigator or scientist.
   [1913 Webster]

WordNet (r) 3.0 (2006):

scientist
    n 1: a person with advanced knowledge of one or more sciences