harmony

First recorded in 1350–1400; Middle English armonye, from Middle French, from Latin harmonia, from Greek harmonía “joint, framework, agreement, harmony,” akin to hárma “chariot,” harmós “joint,” ararískein “to join together”

2. See symmetry. 3. Harmony, melody in music suggest a combination of sounds from voices or musical instruments. Harmony is the blending of simultaneous sounds of different pitch or quality, making chords: harmony in part singing; harmony between violins and horns. Melody is the rhythmical combination of successive sounds of various pitch, making up the tune or air: a tuneful melody to accompany cheerful words.

Harmony comes into English via Latin harmonia “conjunction, joining, (musical) melody, agreement among the various parts of the body (in an explanation of the nature of the soul).” Harmonia comes from Greek harmonía, which has all of the Latin meanings as well as many technical ones, e.g., in music, “octave, mode, pitch (of the voice)”; in philosophy, “framework of the universe, principle of union,” and in the Pythagorean system, the name of the number “three”; in medicine, anatomy, and physiology, “suture, union, temperament”; in law and government, “order, good order, settled arrangement, covenant, agreement.”
Harmonía ultimately derives from the very complicated Proto-Indo-European root ar-, (a)re-, rē-, ṛ- (with still more variants) “to fit, fit together, join.” Reflexes (derivatives) of this root appear in English arm (of the body), Latin arma “equipment, gear, weapons” and armus “(upper) arm.” Farther afield, Hittite has āra- “proper, fitting” and arā- “friend.”
The root variant ṛ- with a suffixed -t forms the noun stems ṛt- and art- “joined together, fitted,” source of Latin ars (stem art- ) “skill, dexterity, art,” artus (noun) and articulus “joint (of the body),” and artus (adjective) “tight, firm.” In the Indo-Iranian languages, ṛt- and art- form the nouns ṛtá- “order, truth, rule” in Vedic Sanskrit and arta (also aša ) “truth, right, justice, right order” in Zoroastrianism, in which arta- is the central principle and the foe of druj “deceit, falsehood, lie.”
Arta- is also the first element of the magnificent Old Iranian names Artavasdes, a Hellenized version of Artavazda (“exalting arta- ”), and Artvardiya “doer of arta- ”; Artaxerxes (Old Persian Artaxšacā ) “having a just kingdom” is from arta- and xšacā “rule, kingdom.” Xérxēs is the Hellenized form of Old Persian Xšyaršā ( Xšayaṛšā, Xšayaršā ) “ruling over heroes.” Xerxes I ruled the Persian Empire 486–465 b.c. He has a thoroughly bad rep: the new Athenian navy won a miraculous victory over his fleet in 480 b.c., and the Spartans and their allies crushed the Persian land forces in 479 b.c. After the debacle against the Greeks, Xerxes devoted himself to wine and women. He is Ahasuerus in the Hebrew Bible, in the Book of Esther.