definite

Having distinct limits.

definite dimensions; a definite measure; a definite period or interval

[…] elements combine in definite proportions […]

Free from any doubt.

definite knowledge

Determined; resolved; decided.

[…] idiots in this case of favour would Be wisely definite

Designating an identified or immediately identifiable person or thing, or group of persons or things

the definite article

A word or phrase that designates a specified or identified person or entity.

Anything that is defined or determined.