Letters that make stay up
s, a, p, t, u, y are letters that make 'stay up'
1 possible definitions for 'stay up'
Under this definition, stay up is a verb and has the following properties:
sit up has the same meaning as stay up
'stay up' can be a type of wake.
"Don't stay up so late--you have to go to work tomorrow", "We sat up all night to watch the election"