means A soft, semi-solid food made from fruit juice or another liquid set with gelatin or pectin, wobbling somewhere between liquid and solid.

from From Old French 'gelee,' meaning a frost or a jelly — itself from the Latin verb 'gelare,' to freeze or congeal. The same chilly root stiffens 'gelatin,' 'gel,' and 'congeal': all of them words about a liquid losing its nerve and firming up. So jelly is, quite literally, something frozen into shape — though it never feels cold, just suspiciously committed to staying put.