What is the meaning of the name 'uthra'?

Interesting- I am reading something about Uthra right now. I wasn't sure what it meant either. It appears in the Mandaean Gnostic texts- in the creation story. Apparently Uthra were the, "the lowest of the angels."

Here's a line:

I, the Life, was brought into being,

and then all the uthras were brought into being.

Sorry, not much info...but it is a start :)