Theory:

Poetry is an art form in which human language is used for its aesthetic qualities in addition to, its notional and semantic content.

It is a form of literature that conveys a thought, describes a scene or tells a story in a concentrated, lyrical arrangement of words.

It may use condensed or compressed form to convey emotion or ideas to the reader's or listener's mind.  It may also use rhetoric devices such as assonance and repetition to achieve the incantation effects.
Nature of poetry: Poetry can be differentiated most of the time from prose, which is language meant to convey meaning in a more expansive and less condensed way.
 
Types of poetry: There are three genres of poetry,
  • Narrative Poetry
  • Dramatic Poetry
  • Lyric Poetry
 
  1. Narrative poetry is a form of poetry that tells a story, often making the voices of a narrator and characters as well.
  2. Dramatic poetry, also known as a dramatic verse or verse drama, is a written work that both tells a story and connects the reader to an audience through emotions or behaviour.
  3. Lyric poetry is a formal type of poetry which expresses personal emotions or feelings, typically spoken in the first person. It is not equivalent to song lyrics, though they are often in the lyric mode.
 
Poetry is broadly divided into two categories, Subjective Poetry and Objective Poetry.
 
The subject matter of the subjective poetry is concerned with the poet's thoughts and feelings. The poet describes 'his own reflection' upon what he has seen or heard. Whatever the subject may be, the poet's mind is centred on his thoughts and feelings. The lyric and elegy represent subjective poetry.
Example:
The definition of subjective is something that is based on personal opinion. An example of subjective is someone believing purple is the best colour—dependent on or taking place in a person's mind rather than the external world.
Objective Poetry is the record of the poet's keen observations and experiences about the things he sees around him. He does not invest his thoughts, feelings and emotions while describing the memorable deeds, events etc., to the work of art.
Example:
Passing an exam is an objective that is necessary to achieve the goal of graduating from a university with a degree.
What is the difference between subjective and objective poetry?
 
Subjective is an adjective, meaning based on or influenced by personal feelings or emotions. Objective is an adjective, which is not based on or influenced personal feelings or emotions, but hard, factual evidence.