Definition of "seventh"

Sozomenus who wrote above twelve hundred years agoe, in his Seaventh Book relates from his own knowledge, that in the Churches of Cyprus and Arabia (places neer to Jeruſalem, and with the firſt frequented by Apoſtles) they had Biſhops in every Village ; and what could thoſe be more then Preſbyters?

1644, Dudley Diggs, The Unlawfulnesse of Subjects Taking up Armes against their Soveraigne, in what Case ſoever, page 158

[H]e, a lollard indeed over his elbovv-cuſhion, in almoſt the ſeaventh part of 40. or 50. years teaches them ſcarce half the principles of religion; and his ſheep oft-times ſit the vvhile to as little purpoſe of benifiting as the ſheep in thir pues at Smithfield; […]

1659, J[ohn] M[ilton], Considerations Touching the Likeliest Means to Remove Hirelings out of the Church. […], London: […] T[homas] N[ewcombe] for L[ivewell] Chapman […], pages 57–58