A versatile word covering both child (young person) and servant (one who serves). The dual meaning reflects the ancient household where children and servants occupied similar positions of dependence and obedience. The LXX uses pais to translate Hebrew ebed (servant), including for the Suffering Servant of Isaiah.
The NT 'servant' titles for Jesus draw on pais: in Acts 3:13 and 4:27, Peter calls Jesus God's pais — his servant/child. This blends sonship with servanthood, fulfilling Isaiah 52-53. Matthew 12:18 quotes Isaiah's Servant songs, identifying Jesus as the pais in whom God delights. The centurion's plea for his pais (Matt 8:6) could mean either his servant or his young attendant — both readings work, showing how the word held both meanings simultaneously.