Thayer's Greek Lexicon

 1. the manager of household or of household affairs
  1) esp. a steward, manager, superintendent (whether free-born or
as was usually the case, a freed-man or a slave) to whom the
head of the house or proprietor has intrusted the management
of his affairs, the care of receipts and expenditures, and the
duty of dealing out the proper portion to every servant and
even to the children not yet of age
  2) the manager of a farm or landed estate, an overseer
  3) the superintendent of the city's finances, the treasurer of a
city (or of treasurers or quaestors of kings)
2. metaph. the apostles and other Christian teachers and bishops
and overseers