In
music and
prosody,
arsis and thesis refer to the stronger and weaker parts of a musical
measure or poetic
foot. Arsis and thesis were the raising and lowering of the
foot in beating of time, or the raising and lowering of the voice in
pitch or
stress. Accordingly, in music and in Greek scansion arsis is an unaccented note (
upbeat), but in Latin and modern poetry it is the stressed syllable (ictus).