What is an example of a stanza?

The lines below are an example of a stanza. In Sonnet 116 by William Shakespeare, the final two lines form a couplet, which is a two-line stanza:

So long as men can breathe or eyes can see,

So long lives this, and this gives life to thee.

A stanza is a group of lines that forms the basic unit of a poem. In a sonnet, there are typically four stanzas: three quatrains (four-line stanzas) and a concluding couplet, like the one shown here.