Source : Webster's Revised Unabridged Dictionary (1913)

Overhead charges \O"ver*head" charges\, expenses \expenses\,
   etc. (Accounting)
   Those general charges or expenses in any business which
   cannot be charged up as belonging exclusively to any
   particular part of the work or product, as where different
   kinds of goods are made, or where there are different
   departments in a business; -- called also fixed,
   establishment, or (in a manufacturing business)
   administration, selling, and distribution, charges, etc.