G3588 "sister's"

G3588 — ho hē to (ho hay to) ὁ ἡ τό: The masculine feminine (second) and neuter (third) forms in all their inflections; the definite article;
the (sometimes to be supplied at others omitted in English idiom): - the this that one he she it etc.

Acts 23 [.mp3]

¹⁶And when Paul's sister's son heard of their lying in wait, he went and entered into the castle, and told Paul.

Colossians 4 [.mp3]

¹⁰¶ Aristarchus my fellowprisoner saluteth you, and Marcus, sister's son to Barnabas, (touching whom ye received commandments: if he come unto you, receive him;)