小姐 xiǎojiě miss

How to remember 小姐: 小 small + 姐 older sister = miss.

Characters

Miss / young lady - a title for a young woman. 王小姐 (Wáng xiǎojiě) Miss Wang.
Register caution: as a standalone address to a stranger (服务员/waitress), 小姐 has picked up a vulgar connotation in mainland China and can offend; 美女 (měinǚ) or 服务员 is safer.
With a surname (李小姐) or in formal/service/Southern/HK-Taiwan contexts it stays polite and neutral.