The Matriculation Album of Glasgow University contains the following entry: 1756, Jacobus McGill, filius natu maximus Jacobi mercatoris Glasguensis.
Nine years later, his younger brother Andrew entered the University, as indicated by the following record in the Matriculation Album: 1765, Andreas McGill, filius natu quintus Jacobi mercatoris Glasguensis.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "natu" in a variety of sentences. We hope that you will now be able to make sentences using this word.