'Custom' in the Bible

Some men came down from Judea and began to teach the brothers: “Unless you are circumcised according to the custom prescribed by Moses, you cannot be saved!”

And on the sabbath day we went outside the gate by the river, where it was the custom for prayer to be, and we sat down and spoke to the women who had assembled.

and according to the custom of Paul, he went in unto them, and for three sabbaths he was reasoning with them from the Writings,

I answered them that it’s not the Romans’ custom to give any man up before the accused confronts the accusers face to face and has an opportunity to give a defense concerning the charges.