What does custom mean? As a noun, custom means alongstanding practice of a person(such as a daily habit) or a group (such as a cultural practice). As an adjective, custom describes something made to unique specifications, especially something one of a kind. Its synonym is custom-made.
Acustomis an activity, a way of behaving, or an event which is usual or traditional in a particular society or in particular circumstances. Thecustomof lighting the Olympic flame goes back centuries.
The meaning ofCUSTOMis a usage or practice common to many or to a particular place or class or habitual with an individual. How to usecustomin a sentence. Synonym Discussion ofCustom.

If something has been done a certain way for a long time and has become generally accepted, it's acustom. Asking strangers for candy on one night a year would seem strange if it weren't an establishedcustom.
Some common synonyms ofcustomare habit, practice, usage, and wont. While all these words mean "a way of acting fixed through repetition,"customapplies to a practice or usage so steadily associated with an individual or group as to have almost the force of unwritten law.

Acustomis an activity, a way of behaving, or an event which is usual or traditional in a particular society or in particular circumstances.