1. To continue to be at a raised or higher position. The flags should remain up throughout the entire ceremony. Don't lower them until everyone has left the stage. I don't want our Christmas lights remaining up all the way into the spring like they did last year!
2. To continue to be displayed in a prominent place or position. The judge ruled that the inflammatory posters could remain up, as they were under the protection of the first amendment. She apologized for her rude remarks on social media, but they remained up for days afterward.
3. To continue to be awake. My mom usually remains up until around 12 o'clock, so we definitely won't be able to sneak out without her noticing. You're always complaining about how tired you are, so I don't know why you remain up so late each night.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
to stay awake and out of bed. I remained up throughout most of the night. I cannot remain up much longer.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.