The greek word for "steward" is oykonomos.

Oykonomos is a compund word of oikos (home or house) and nomos (rule). It is used in the sense of a servant who manages a house. This is particularly appropriate in the context of 1Corinthians chapter 4 because in chapter three Paul had just explained the part he played in building God's house. It is a house under construction---the church.

The master has left rules for his stewards to follow as they work on the house.