gel (n.) Look up gel at Dictionary.com
"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 (1805-1869). Hair-styling sense is from 1958.
gel (v.) Look up gel at Dictionary.com
1902, "to become a gel," from gel (n.). Figurative sense "come together and agree well" is from 1958. Related: Gelled; gelling.