Enclosed rhyme (or enclosing rhyme) is the rhyme scheme "abba" (that is, where the first and fourth lines, and the second and third lines rhyme). Enclosed-rhyme quatrains are used in introverted quatrains, as in the first two stanzas of Petrarchan sonnets. A rhyme scheme is like the pattern of rhyming like lines in a poem or in like lyrics for music. ... A quatrain is a poem or a stanza within a poem that consists of four lines. ... A Petrarchan sonnet, also called the Italian sonnet, is a sonnet comprising an octave and a closing sestet. ...
Example
How soon hath Time, the subtle thief of youth,
Stolen on his wing my three and twentieth year!
My hasting days fly on with full career,
But my late spring no bud or blossom shew'th.
(From John Milton's "On His Being Arrived to the Age of Twenty-Three")
John Milton, English poet John Milton (December 9, 1608 â November 8, 1674) was an English poet, best-known for his epic poem Paradise Lost. ...