Ettandales was cold frozen land north of Rivendell.It was inhabited by Trolls
Another name for land of highlands and valleys otherwise known as Ettenmoors or the Coldfells.These were cold lands far to the north of Rivendell and little known to any but the Trolls that inhabited them. Aragorn's grandfather Arador had ventured into these hills and dales but he was captured and killed by the Snow-trolls that lurked there.
Ettendales are literally 'giant-valleys'.It's unclear how literally 'giants' are meant and this may simply be a reference to the Trolls we know lived in this region.On the other hand this may be a hint that the Ettendales are home to the actual Giants. 'etten'- comes from Old English eoten meaning Giant.