Meaning ofbutton upin English

Verb

1. to fasten with buttons; secure clothing
   You should button up your coat to stay warm.
2. to remain silent (and keep a secret)
   The company will button up the facility for the holiday.
3. to keep warm by fastening all buttons
   Please button up and don't say a word about the surprise.
4. to seal off a vehicle or facility (for protection)
   In cold weather, remember to button up your jacket.