Ăr'sis, n.
[Lat. arsis, Gr. ἄρσις, a raising or lifting, an elevation of the voice, from αἴρειν, to raise or lift up. Its ordinary use is the result of an early misapprehension; originally and properly it denotes the lifting of the hand in beating time, and hence the unaccented part of the rhythm.]
Sense 1. (Pros.) (a.) That part of a foot where the ictus is put, or which is distinguished from the rest of the foot by a greater stress of voice. Hermann. (b.) That elevation of voice now called metrical accentuation, or the rhythmic accent. It is uncertain whether the arsis consisted in a higher musical tone, greater volume, or longer duration of sound, or in all combined. P. Cyc.
Sense 2. (Mus.) (a.) The rising of the hand in beating time. (b.) That part of the measure in which the hand rises. P. Cyc.