'Custom' in the Bible

it fell to his lot--according to the custom of the priesthood--to go into the Sanctuary of the Lord and burn the incense;

Led by the Spirit he came to the Temple; and when the parents brought in the child Jesus to do with regard to Him according to the custom of the Law,

He came to Nazareth also, where He had been brought up; and, as was His custom, He went to the synagogue on the Sabbath, and stood up to read.