Source : Webster's Revised Unabridged Dictionary (1913)

Loggerhead \Log"ger*head`\, n. [Log + head.]
   1. A blockhead; a dunce; a numskull. --Shak. Milton.

   2. A spherical mass of iron, with a long handle, used to heat
      tar.

   3. (Naut.) An upright piece of round timber, in a whaleboat,
      over which a turn of the line is taken when it is running
      out too fast. --Ham. Nav. Encyc.

   4. (Zo["o]l.) A very large marine turtle ({Thalassochelys
      caretta, or caouana}), common in the warmer parts of the
      Atlantic Ocean, from Brazil to Cape Cod; -- called also
      {logger-headed turtle}.

   5. (Zo["o]l.) An American shrike ({Lanius Ludovicianus}),
      similar to the butcher bird, but smaller. See {Shrike}.

   {To be at loggerheads}, {To fall to loggerheads}, or {To go
   to loggerheads}, to quarrel; to be at strife. --L' Estrange.