一旦[ittan] once
元旦[gantan] New Year's Day
旦那[danna] master (of a house, shop, etc.)
巴旦杏[hatankyou] plum
文旦[buntan] shaddock

旦つく[dantsuku] husband
命旦夕に迫る[meitansekinisemaru] to be on the brink of death
旦夕[tanseki] on the brink of
若旦那[wakadanna] young master
大旦那[oodanna] master