The Collaborative International Dictionary of English v.0.48:

Char \Char\ (ch[aum]r), v. t. [imp. & p. p. Charred
   (ch[aum]rd); p. pr. & vb. n. Charring.] [Prob. the same
   word as char to perform (see Char, n.), the modern use
   coming from charcoal, prop. coal-turned, turned to coal.]
   1. To reduce to coal or carbon by exposure to heat; to reduce
      to charcoal; to burn to a cinder.
      [1913 Webster]

   2. To burn slightly or partially; as, to char wood.
      [1913 Webster]