'Once' in the Bible

for the king’s ships kept going to Tarshish with Hiram’s servants, and once every three years the ships of Tarshish would arrive bearing gold, silver, ivory, apes, and peacocks.

Jehoshaphat lived in Jerusalem, and once again he went out among the people from Beer-sheba to the hill country of Ephraim and brought them back to Yahweh, the God of their ancestors.