(Latin: make right or lawful)
Removal of the irregularity due to birth out of wedlock.
In canon law all children of marriage are presumed to be legitimate even though the marriage be invalid but reputed valid, or declared null after the birth of the children.
Illegitimacy is removed if the parents marry, provided they were entitled to marriage at the time of the conception or birth or at some intermediate time, and this removal extends to children already deceased, and to their descendants.
Legitimation does not depend on the will of the parents.
The sovereign pontiff has thc power of legitimating anyone born out of wedlock, and of removing irregularities that would prevent them from receiving priestly orders and from advancing to higher ecclesiastical offices.
New Catholic Dictionary