Formal:
* 公主 (gōng zhǔ): This is the most common and formal word for princess. It literally means "imperial daughter" and refers to the daughter of an emperor or king.
Informal:
* 小公主 (xiǎo gōng zhǔ): This is a more informal and endearing term, literally meaning "little princess." It's often used for young girls or to refer to someone who is treated like royalty.
Other options:
* 郡主 (jùn zhǔ): This term refers to a princess of a lower rank, typically the daughter of a prince or duke.
* 王妃 (wáng fēi): This term actually refers to the wife of a prince, but it can sometimes be used to refer to a princess as well, particularly in older historical texts.
The specific term you choose will depend on the context and the level of formality you want to convey.