Arlo (pronounced AR-loh) is a given name for males. From Old English, it is believed to be derived from the Anglo-Saxon here 'army, fortified, troops; war-' and hlaw 'mound, cairn, hill,' thereby meaning 'fortified hill.' Arlo can also be a variant of Harley and the first formant in Arlene, which derive from Old English har "hare", "rabbit" and ear(n) "eagle". The second formant, giving -lo(w), -l(e)y, etc. are topographic names, such as the hlaw mentioned above. For example, the ancestors of today's lee (and name Lee), loch, etc.