Heptameter is a line of verse made up of seven metrical feet. In English poetry, it often appears as a long, rolling line and may be described more specifically by its pattern, such as iambic heptameter.
Example
Shadows cross the garden while the evening bells are calling
Silver dew lies cold upon the grass before the dawn
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!