What does ann or annat mean?
The definition of ann and annat
Ann, An”nat, n.
Etym: [LL. annata income of a year, also, of half a year, fr. L. annus year: cf. F. annate annats.] (Scots Law)

A half years’s stipend, over and above what is owing for the incumbency, due to a minister’s heirs after his decease.