difference between epitaph and elegy poems?

anyone know difference between epitaph and elegy poems? (school thing...)

ep·i·taph
An inscription on a tombstone in memory of the one buried there.

A brief literary piece commemorating a deceased person.



el·e·gy
A poem composed in elegiac couplets.

A poem or song composed especially as a lament for a deceased person. Something resembling such a poem or song.

Music. A composition that is melancholy or pensive in tone.

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