late 14c., progressioun, "action of moving from one condition to another," from Old French progression and directly from Latin progressionem (nominative progressio) "a going forward, advancement, growth, increase," noun of action from past-participle stem of progredi "go forward," from pro "forward" (see pro-) + gradi "to step, walk," from gradus "a step" (from PIE root *ghredh- "to walk, go"). The musical sense of "an advance from one note to another" or later one chord to another is by c. 1600. Related: Progressional.
1620s, "pertaining to geometry," shortened form of geometrical (q.v.). In reference to a style of ancient Greek pottery decoration characterized by straight lines and angles, and the associated culture, 1902.
in mathematics, 1941, probably from isometric (q.v.) on the model of geometry/geometric.
slightly earlier and more classical form of rhomb (q.v.), 1560s, from Late Latin rhombus, in the geometric sense.
"the act of going backward," in reference to the apparent motion of planets in the sky, 1640s, noun of action, formed on model of progression, from Latin retrogressus, past participle of retrogradi "move backward" (see retrograde). Related: Retrogressional.