1. Duties or tax charged on goods imported into a country
   "They had to pay impost duty on the imported luxury goods";
   - customs, customs duty, custom
    
2. The lowest stone in an arch — from which it springs
   "The impost was decorated with intricate carvings";
   - springer

Derived forms: imposts

Type of: duty, stone, tariff

Part of: arch

Encyclopedia: Impost