The word syllabus was first used in English in 1656 by lexicographer Thomas Blount in a dictionary listing out a bunch of difficult loanwords. Then, it was described as "a Table or Index in a Book, to shew places or matter by Letters or Figures". Before that, syllabus was used in Medieval Latin, and that was taken from Ancient Greek sittybos. The reason for the sound change is quite interesting: it was supposed to be syttabus, but some fifteenth-century scholar translating Cicero's Ad Atticum misprinted the ts as ls, probably because they confused the word with the unrelated Ancient Greek verb syllambano, "to put together". The real etymon is unknown, but it probably had something to do with parchment. Unsurprisingly, Google Trends shows searches for syllabus peaking in August and January - the beginning of school semesters.
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.