What does advowson mean?
The definition of advowson
Ad*vow”son, n.
Etym: [OE. avoweisoun, OF. avoëson, fr. L. advocatio. Cf. Advocation.] (Eng. Law)

The right of presenting to a vacant benefice or living in the church. [Originally, the relation of a patron (advocatus) or protector of a benefice, and thus privileged to nominate or present to it.]

Note: The benefices of the Church of England are in every case subjects of presentation. They are nearly 12,000 in number; the advowson of more than half of them belongs to private persons, and of the remainder to the crown, bishops, deans and chapters, universities, and colleges. Amer. Cyc.