custom
/ˈkə-stəm/
noun
a usage or practice common to many or to a particular place or class or habitual with an individual
long-established practice considered as unwritten law
repeated practice
It is the custom in New Orleans to celebrate Mardi Gras.
adjective
made or performed according to personal order
specializing in custom work or operation
adjective
built to individual specifications
a custom-built house