What is Customs ?
Customs is (noun) 1. H.M. Customs and Excise the British government department which organises the collection of taxes on goods coming into the country and also collects VAT He was stopped by customs. Her car was searched by customs. The customs officer asked her to open her bag. 2. an office of this department at a port or airport to go through customs to pass through the area of a port or airport where customs officials examine goods When you come into the country, you have to go through customs. to take something through customs to carry something through the customs area without always declaring it She said that her boyfriend had asked her to take the case through customs for him.
source: Easier English, Student Dictionary Upper Intermediate Level