A symbol is always something that represents something else and designates a type of sign in which concrete reality represents something abstract (as in the case of the cross that represents Christianity).
In the line shown above, the term "my wings" symbolizes something of the narrator who has taken him down. In this line, the symbol represents an essential element in the process of communication of the poem, which is spread by the most varied strands of human knowledge, since always, and intensifies the relationship with the transcendent.
