can u explain what is meant by dramatic monologue

A dramatic monologue is a poetic form. The poet creates a
character - either imaginary or historical - who is speaking to an imaginary audience. 
He is the only character --- hence the term "monologue" During his speech he reveals
something important about himself.  An example of a dramatic monologue would be William
Wordsworth's "Tintern Abbey"   It begins with the speaker stating that he hasn't visited
the area in five years.  He describes the cliffs, the sycamore tree, the cottage
grounds, and the orchard trees.  Then he describes how the memory of these "beauteous
forms" has provided him with sweet memories and a "tranquil restoration" of his mind in
times of "fretful stir"