NOUN (3)

1. a workman who uses a tool for scratching;

2. a person who scratches to relieve an itch;

3. a device used for scratching;

The Collaborative International Dictionary of English v.0.48:

Scratcher \Scratch"er\, n.
   One who, or that which, scratches; specifically (Zool.), any
   rasorial bird.
   [1913 Webster]

WordNet (r) 3.0 (2006):

scratcher
    n 1: a workman who uses a tool for scratching
    2: a person who scratches to relieve an itch
    3: a device used for scratching