:a usage or practice common to many or to a particular place or class or habitual with an individual
- It is the custom in New Orleans to celebrate Mardi Gras.
:long-established practice considered as unwritten law
- Custom makes all things easy.
:the whole body of usages, practices, or conventions that regulate social life
- … family, kinship, and custom constituted the grounds of community.
- —V. B. Leitch
:duties, tolls, or imposts imposed by the sovereign law of a country on imports or exports
usually singular in construction
:the agency, establishment, or procedure for collecting such customs
- went through customs at the airport without any difficulty