As a reader, you may find it hard to speak frankly in the poet's presence about words, images, and ideas charged with personal expression. Yet in doing so, you help the writer see how the poem affects another person, and how it might evolve in a future draft.
In poetry, stanzas are visual groupings of lines. A group of two lines is called a couplet. A three line stanza is called a tercet. A four line stanza is a quatrain, and a five line stanza is a quintet. Two other common lengths are a sestet, six lines; and an octave, eight lines.