namam no. 377) devah (देवः) (దేవః)

aum deavaaya namah (ओं देवाय नमः) (ఓం దేవాయ నమః)

He is called devah as He traps the beings in the cage of maaya and plays with them in the same manner as the animals were tied and caged with ropes and chains.

Here, the threefold nature (trigunaatmaka prakriti) of humans itself has become the rope that traps the people in the cycle of samsaara. He is called 'devah' as He traps them according to their deeds of paapa (sin) in the cage of body with such a rope of their own nature. 
aum namo bhagavate vasudevaya!

PS: For the meanings of the other namams published earlier on this blog, please find them at the link given below:

http://value4value.blogspot.in/search/label/Vishnu%20Sahasra%20Nama%20Stotram