Elegiacs are classical verse couplets made of one line of dactylic hexameter followed by one line of dactylic pentameter. Together, the two lines form an elegiac couplet, a pattern used in Greek and Latin poetry for laments, reflections, love poems, and short epigram-like pieces.
The term can also be used more loosely for poems written in or imitating that couplet form.
Example
Time gathers the olives, then leaves the bare branch behind;
Night lowers its cool hand gently over the sea.