The word "korekta" is derived from the verb "korekti", which means "to correct". Therefore its only regular meaning is "characterized by or related to the act of correcting". For example, one can say "korekta laboro" in the sense of "correction work", i.e. the work that consists of correcting something. PIV has another good example: "la korektaj reguloj de presejo", i.e. the rules that a printing house has defined concerning how to correct manuscripts. Note, however, that this regular meaning of "korekta" is only very rarely needed.

Also note that while it is right to say that "correct" cannot be a regular meaning of "korekta", "korekta" has been used in the sense of "correct" by many competent Esperanto speakers, including Zamenhof himself (in his late years). So one can say that "korekta" does in the actual usage have this meaning, even though it is not a regular meaning.

But also note that many competent Esperanto speakers avoid the usage of "korekta" in the sense of "correct" because of its irregularity, as they want to contribute to Esperanto usage becoming more in line with the general rules. The most respected dictionary (PIV) and the most respected grammar (PMEG) both recommend avoiding "korekta" in the sense of "correct". Instead, one should use "ĝusta" or "senerara", depending on context.