customs vs procedures

customs

noun
  • The duties or taxes imposed on imported or exported goods. 

  • The location at a border checkpoint where customs checks are carried out. 

  • The government department or agency that is authorised to collect the taxes imposed on imported goods. 

  • The process of going through customs checks at a border checkpoint. 

procedures

How often have the words customs and procedures occurred in a corpus of books? (source: Google Ngram Viewer )