noun · doctor (as an academic degree); PhD holder

他正在努力攻读物理学博士学位。

noun · an official or scholar-official in ancient China; court academician

朝廷任命他为五经博士，在太学传授经典。

noun · a person specialized in a specific trade or skill in ancient times

茶博士正熟练地为茶馆里的客人斟茶。