gelatinous adj.

1713, from French gélatine (17c.) "clear jelly-like substance from animals; fish broth," from Italian gelatina, from gelata "jelly," from gelare "to jell," from Latin gelare "to freeze, congeal" (from PIE root *gel- "cold; to freeze"). With chemical suffix -ine (2). Spelling gelatin is from 1800. "The form without final -e is in scientific (or pseudo-scientific) use only ..." [Fowler].

word-forming element making adjectives from nouns, meaning "having, full of, having to do with, doing, inclined to," from Old French -ous, -eux, from Latin -osus (compare -ose (1)). In chemistry, "having a lower valence than forms expressed in -ic."

Proto-Indo-European root meaning "cold; to freeze." 

It forms all or part of: chill; cold; congeal; cool; gel; gelatine; gelatinous; gelato; gelid; glace; glacial; glaciate; glaciation; glacier; glaciology; glacis; jell; jelly.

It is the hypothetical source of/evidence for its existence is provided by: Latin gelare "to freeze," gelu "frost," glacies "ice;" Old English cald "cold, cool," German kalt.