What is the meaning of Certain?

Sure in one's mind, positive; absolutely confident in the truth of something.

Particular and definite, but unspecified or unnamed; used to introduce someone or something without going into further detail.

Named but not previously mentioned.

Used before the name of someone famous that people are expected to know.

Determined; resolved.

Having been determined but not specified.

Unnamed or undescribed members (of).

certain, for certain, indubitably

certain (of indefinite, unknown or simply unmentioned identity, quality or quantity)

certain (sure, positive)

certain (fixed, determined)

certain (specified, particular)

Source: wiktionary.org

See also