What does Walter mean?
From Germanic 'wald' (rule, power) and 'heri' (army), giving 'ruler/commander of the army'. Brought to England by the Normans.
What does Herman mean?
From Germanic 'heri' (army) and 'man' (man), giving 'man of the army, soldier'. The Latinized Arminius refers to the same Cheruscan war-leader.