an action or official decision that can be used to give support to later actions or decisions:
set/create a precedent
UN involvement in the country's affairs would set a dangerous precedent.
precedents for what courts will accept as 'fair'
2 [uncountable and countable]
something of the same type that has happened or existed before
There's not much precedent for men taking leave when their baby is born.
An epidemic on this scale is without precedent.
the way that things have always been done
break with precedent (=do something in a new way)