The Greek neuter noun doulon is a form of doulos meaning slave or servant, used in contexts describing servanthood or bondage without gender specification.
Doulon captures the theological concept of servanthood that pervades the New Testament. In Galatians 4:7, Paul uses the slave/son contrast to explain the transformation brought by faith in Christ: 'So you are no longer a slave, but God's child; and since you are his child, God has made you also an heir.' This word marks the before and after of redemption: once in bondage, now adopted as children and heirs. The doulon imagery also underscores that belonging to God — even as His servant — is an identity of honor, not shame.