harmonic motion Date: 1867 : a periodic motion (as of a sounding violin string or swinging pendulum) that has a single frequency or amplitude or a periodic motion that is composed of two or more such simple periodic motions

over·tone Date: 1867 1 a : one of the higher tones produced simultaneously with the fundamental and that with the fundamental comprise a complex musical tone 2 : the color of the light reflected (as by a paint)   

accent 3 : rhythmically significant stress on the syllables of a verse usually at regular intervals 6 a : greater stress given to one musical tone than to its neighbors

me·ter Middle English, from Old English & Middle French; Old English mEter, from Latin metrum, from Greek metron measure, meter; Middle French metre, from Old French, from Latin metrum -- more at MEASURE. before 12th century 1 a : systematically arranged and measured rhythm in verse: (1) : rhythm that continuously repeats a single basic pattern <iambic meter> (2) : rhythm characterized by regular recurrence of a systematic arrangement of basic patterns in larger figures <ballad meter> 4 c : a fixed metrical pattern : verse form 2 : the basic recurrent rhythmical pattern of note values, accents, and beats per measure in music 

mea·sure  4 a (1) : MELODY, TUNE (2) : DANCE; especially : a slow and stately dance b : rhythmic structure or movement : CADENCE: as (1) : poetic rhythm measured by temporal quantity or accent; specifically : METER (2) : musical time c (1) : a grouping of a specified number of musical beats located between two consecutive vertical lines on a staff

tem·po Italian, literally, time, from Latin tempus circa 1724. 1 : the rate of speed of a musical piece or passage indicated by one of a series of directions (as largo, presto, or allegro) and often by an exact metronome marking. 2 : rate of motion or activity : PACE 

a tem·po Italian circa 1740 : in time -- used as a direction in music to return to the original tempo

allegro tempo