In poetry, what does close reference mean?

Marna Liddie: looking at every word in a line and its significance for the whole structure of the poem, e.g. "I wandered lonely as a cloud" - close reference would by saying something about the personal pronoun "I", and "lonely" means solitariness in nature due to the "cloud" and the construction of the simile with "as". in some cases, looking at etymology, rhythm, rhyme, meter and alliteration is also close reading.