Other forms: spectacles
A spectacle is an impressive public display — or a shameful sight nobody can look away from. The word carries both.
The grand sense covers ceremonies, fireworks and opening ceremonies, so a spectacle is something staged to be watched. The other sense lives in one phrase, since making a spectacle of yourself means behaving so badly in public that people stare. The plural is different again, since spectacles are glasses, which is why an optician's is full of them. The adjective spectacular has kept only the impressive meaning.
A spectacle is a thing to be looked at, over and over. Latin spectāculum comes from spectō, the repeated form of speciō, to see, so the word is built out of staring.
Proto-Indo-European
*speḱ-
Latin
spectāculum — a show, spectacle
Middle French
spectacle
Middle English
spectacle
English, today
spectacle
Built from
From Middle English spectacle, from Middle French spectacle, from Latin spectāculum (“a show, spectacle”), from spectō (“to see, behold”), frequentative of speciō (“to see”). See species. a doublet of spectaculum.
Etymology from Wiktionary, CC BY-SA