alto n.

Proto-Indo-European root meaning "to grow, nourish."

It forms all or part of: abolish; adolescent; adult; alderman; aliment; alimony; Alma; alma mater; alt (2) "high tone;" alti-; altimeter; altitude; alto; alumnus; auld; coalesce; elder (adj., n.1); eldest; Eldred; enhance; exalt; haught; haughty; hautboy; hawser; oboe; old; proletarian; proliferation; prolific; world.

It is the hypothetical source of/evidence for its existence is provided by: Greek aldaino "make grow, strengthen," althein, althainein "to get well;" Latin alere "to feed, nourish, suckle; bring up, increase," altus "high," literally "grown tall," almus "nurturing, nourishing," alumnus "fosterling, step-child;" Gothic alþeis, Dutch oud, German alt "old;" Gothic alan "to grow up," Old Norse ala "to nourish;" Old Irish alim "I nourish."

"voice intermediary between the soprano and the tenor, lowest female voice," 1730, contralt, from Italian contralto, from contra, from Latin contra "against, opposite" (see contra) + alto (see alto). As "person with a contralto voice," 1776; as an adjective, 1769.

In medieval music, in which the melody was either in a middle voice or passed from one voice to another, and which utilized only male singers, the upper voice was naturally called altus. As music for mixed voices developed, that female voice which was nearest the altus, and thus most contrasted with it, was called contr' alto. [Century Dictionary]

c. 1300, "general meaning, prevailing course, purpose, drift," from Old French tenor "substance, contents, meaning, sense; tenor part in music" (13c. Modern French teneur), from Latin tenorem (nominative tenor) "a course," originally "continuance, uninterrupted course, a holding on," from tenere "to hold," from PIE root *ten- "to stretch." The musical sense of "high male voice" is attested from late 14c. in English, so-called because the sustained melody (canto fermo) was carried by the tenor's part. Meaning "singer with a tenor voice" is from late 15c. As an adjective in this sense from 1520s.