One or more lines of verse containing seven metrical feet (usually fourteen or twenty-one syllables).
Example
An example from Lord Byron's Youth and Age:
'Tis but as ivy-leaves around the ruin'd turret wreathe, All green and wildly fresh without, but worn and gray beneath. O could I feel as I have felt, or be what I have been, Or weep as I could once have wept o'er many a vanish'd scene,- As springs in deserts found seem sweet, all brackish though they be, So midst the wither'd waste of life, those tears would flow to me!