Nullius filius is a Latin phrase that translates to "son of nobody" or "son of no one." There are several synonymous phrases that can be used in place of nullius filius, such as "son of unknown parents," "illegitimate child," or "child of uncertain paternity." These phrases are often used in legal contexts to describe children without known or acknowledged parents. The term nullius filius also has historical significance, as it was used in medieval and early modern England to refer to children born out of wedlock or to unknown fathers. Today, there is a greater effort towards respecting and acknowledging the rights of all children, regardless of their family or birth circumstances.