The term elegy has a long history. It originally, in ancient Greece, had two meanings. The first was a sorrowful or mournful poem sung to the accompaniment of aulos (an instrument sounding like a modern oboe). The second meaning referred to the meter in which such songs were often written, elegiac couplets, which consist of a hexameter followed by a pentameter line. One of the best imitations of this form in English is Coleridge's:

In the hexameter rises the fountain's silvery column;

In the pentameter aye falling in melody back.

As the form originated in songs of lament, and funerals are a common occasion for lamentation, the elegy evolved to become closely associated with funerals or laments over someone's death.

"Elegy Written in a Country Churchyard" by Thomas Gray is not written in elegiac couplets, but it is set in a graveyard and expresses mourning for death. It may have been written on the death of Gray's friend Richard West in 1742, but is itself a more general lament concerning human mortality.

The poem has a sustained melancholic tone. It begins with the line:

The curfew tolls the knell of parting day

This draws a parallel between the end of day and the end of human life in the graveyard. The elegiac tone is created by a series of terms suggesting absence, fading, sadness, weariness, darkness, and departure in the initial stanzas as well as images of solitude, twilight, and abandonment.

"Elegy" comes from the Greek word élegos, meaning "funeral lament." The meaning soon altered so that Latin as well as English elegies, while still poems about death, tend to be melancholic and reflective in tone rather than sharp or piercing. The elegiac tone of Gray's "Elegy Written in a Country Churchyard" is evident from the very first words of the poem. Bells are ringing to signal the end of the working day, and darkness falls upon the landscape. The churchyard is so quiet that slight and distant sounds are clearly audible, and there is a pervasive atmosphere of "solemn stillness."

The tone of general melancholy in Gray's poem is enhanced by the fact that the poet is not mourning a specific loved one. Thus the tone is not grief-stricken; the sadness the poet feels is at both the common lot of humanity, which is inevitable death, and at the waste of talent represented by these graves. As well as being sad, Gray's diction and imagery are elevated, with somber imagery enhancing the majesty of death:

But Knowledge to their eyes her ample page

Rich with the spoils of time did ne'er unroll;

Chill Penury repress'd their noble rage,

And froze the genial current of the soul.

What is the universality of "Elegy Written in a Country Churchyard" by Thomas Gray?

While some elements of "Elegy Written in a Country Churchyard" by Thomas Gray could be considered universal, others are prototypically English. 

The landscape, farming methods, and church bells tolling at sunset create an atmosphere specific to Northern Europe and the British isles. The romanticization of the pastoral life is part of a western tradition of pastoral elegy dating back to the Hellenistic poets, and thus common to much of western literature, but it is still not universal. The references in the poem to heroic figures such as Milton, Hampden, and Cromwell are also grounded in a specific place and time. The Christian background to the poem is also not universal, as Christianity is one of many world religions.

The main aspect of the poem that is universal is its treatment of death, as all living beings eventually die. The next element that is universal is its reflection on the relationship of the death of average people to the death of famous people. Both are mourned equally by their families and friends, and sub specie aeternitatis, all deaths are equally significant. Finally, the notion that circumstances make the difference between the famous and influential and the humble -- that many people in the village may have had the same innate abilities as important historical figures -- is also universal.