Real Dictionary

stand up
phrasal verb: If a boyfriend or girlfriend stands you up, they fail to keep an arrangement to meet you.
phrasal verb: If something such as a claim or a piece of evidence stands up, it is accepted as true or satisfactory after being carefully examined.

stand up in American English
to come to or remain in a standing position
adjective: standing erect or upright, as a collar

stand up in British English
to rise to the feet

stand-up
A stand-up comic or comedian stands alone in front of an audience and tells jokes.

stand-up in British English
standing upright or erect
to rise to or be in a standing position
adjective: of or relating to the act of standing alone in front of an audience and performing comedy or telling jokes
noun: the act of standing alone in front of an audience and performing comedy or telling jokes