Wordnet 3.0
VERB (1)
1. 
 cease to operate or cause to cease operating; 
- Example: "The owners decided to move and to close the factory"- Example: "My business closes every night at 8 P.M."- Example: "close up the shop"[syn: close up, close, fold, shut down, close down]
WordNet (r) 3.0 (2006):
close down
    v 1: cease to operate or cause to cease operating; "The owners
         decided to move and to close the factory"; "My business
         closes every night at 8 P.M."; "close up the shop" [syn:
         close up, close, fold, shut down, close down]
         [ant: open, open up]