gelatin (n.)

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].

"semi-solid substance," 1899, as a chemical term, short for gelatin and perhaps influenced by jell. The invention of this word is credited to Scottish chemist Thomas Graham. Hair-styling sense is from 1958.