'Syllable' is Greek for 'sounds taken together' — a clutch of sounds forming one beat of speech.
A unit of pronunciation having one vowel sound, with or without surrounding consonants, forming the whole or part of a word.
From Old French sillabe, from Latin syllaba, from Greek sullabḗ (συλλαβή), meaning a taking together, a combination of letters, a syllable. Formed from sun- (together, with) + lambanein (to take, to seize), where sun- derives from Proto-Indo-European *sem- (one, together) and lambanein traces to PIE *leh₂gʷ- (to seize, to catch). The linguistic concept Greek grammarians named was exactly this: a syllable is the taking together of consonants
'Syllable' and 'syllabus' look related and are: Greek 'syllabḗ' (things taken together) was misread in a medieval manuscript of Cicero as 'syllabus,' which was then taken to mean 'a list' (things gathered together). So 'syllabus' is actually a ghost word — a scribal error that became a real word. The Vatican's 1864 'Syllabus of Errors' cemented its usage.