A dialogue (sometimes spelled dialog) is a reciprocal conversation between two or more entities. The etymological origins of the word (in Greek διά("diá," through) and λόγος ("logos," word, speech) creating concepts such as flowing-through meaning) do not necessarily convey the way in which people have come to use the word, with some confusion between the prefix διά-("diá-," through) and the prefix δι-("di-," two) leading to the erroneous assumption that a dialogue is necessarily between only two parties.

Literary and philosophical genre

When reported or imitated in writing, "dialogue" labels a form of literature used by Greeks and Indians for purposes of rhetorical entertainment and instruction. This form has scarcely been modified since the days of its birth.

A literary dialogue comprise of drama in a sentence. It has long served writers who have something to censure or to impart, but who love to stand outside the pulpit, and to encourage others to pursue a train of thought which the author does not seem to do more than indicate. The dialogue expresses and notes down the undulations of human thought so spontaneously that it almost escapes analysis. Commonly, records of the alleged actual words spoken by living or imaginary people and it appears in a dialogued format. One branch of this form of expressive documentation, the drama, depends upon dialogue almost exclusively. Yet, in its technical sense, the word 'dialogue' describes what the Greek philosophers invented, and what the noblest of them lifted to the extreme refinement of an art.

Antiquity and the middle ages

In the east, the genre dates back to the Sumerian dialogues and disputations (preserved in copies from the early second millennium b.c.e.), as well as Rigvedic dialogue hymns and the Indian epic Mahabharata, while in the west, literary historians commonly suppose that Plato (c. 427 BC - c. 347 BC) introduced the systematic use of dialogue as an independent literary form: they point to his earliest experiment with the genre in the Laches. The Platonic dialogue, however, had its foundations in the mime, which the Sicilian poets Sophron and Epicharmus had cultivated half a century earlier. The works of these writers, which Plato admired and imitated, have not survived, but scholars imagine them as little plays usually presented with only two performers. The Mimes of Herodas give us some idea of their scope.

Plato further simplified the form and reduced it to pure argumentative conversation, while leaving intact the amusing element of character-drawing. He must have begun this about the year 405 BC, and by 399 he had brought the dialogue to its highest perfection, especially in the cycle directly inspired by the death of Socrates. All his philosophical writings, except the Apology, use this form. As the greatest of all masters of Greek prose style, Plato lifted his favorite instrument, the dialogue, to its highest splendor, and to this day he remains by far its most distinguished proficient.