'Custom' in the Bible

Some men came down from Judea and began teaching the brethren, “Unless you are circumcised according to the custom of Moses, you cannot be saved.”

And according to Paul’s custom, he went to them, and for three Sabbaths reasoned with them from the Scriptures,

I answered them that it is not the custom of the Romans to hand over any man before the accused meets his accusers face to face and has an opportunity to make his defense against the charges.