GNU Collaborative International Dictionary of English

Found one definition

1.       
   customs n. pl.
   1. money collected under a tariff; a duty imposed on imported goods.
   
   Syn. -- customs duty, custom, impost.
   
   [WordNet 1.5]
   
   
   2. the government department administering the collection of import tariffs.  Used with as singular verb.
   
   [PJC]
   
   
   3. that area within an airport, sea port, or other border station where freight or the baggage of travellers is checked for dutiable materials or contraband; as, “it took an hour to get through customs”.
   
   [PJC]