What does adown mean?
The definition of adown
A*down”, adv.
Etym: [OE. adun, adoun, adune. AS. of dune off the hill. See Down.]

From a higher to a lower situation; downward; down, to or on the ground. [Archaic] “Thrice did she sink adown.” Spenser.

A*down”, prep.
Down. [Archaic & Poetic] Her hair adown her shoulders loosely lay displayed. Prior.