Definition of "gel"

gel¹

/d͡ʒɛl/

noun
countable and uncountable, plural gels
1. A semi-solid to almost solid colloid of a solid and a liquid, such as jelly, cheese or opal.
  Quotations
  Similar studies of rats have employed four different intracranial resorbable, slow sustained release systems—surgical foam, a thermal gel depot, a microcapsule or biodegradable polymer beads.
  2013 May-June, Charles T. Ambrose, “Alzheimer’s Disease”, in American Scientist, volume 101, number 3, page 200
2. Any gel intended for a particular cosmetic use, such as for styling the hair.
verb
third-person singular simple present gels, present participle gelling, simple past and past participle gelled
1. (transitive) To apply (cosmetic) gel to (the hair, etc).
  Quotations
  It ended, as it so often does, with that familiar smile. Cristiano Ronaldo – gelled hair, dazzling teeth, magic in his boots – will never forget the night he scored the 600th goal of an almost implausible career.
  2017 June 3, Daniel Taylor, “Real Madrid win Champions League as Cristiano Ronaldo double defeats Juv”, in The Guardian (London)‎
2. (intransitive) To become a gel.
3. (intransitive) To develop a rapport.
4. (intransitive, figurative) To come together to form something; to cohere.

gel²

/ɡɛl/

noun
plural gels
1. (Britain, slang) A girl.
  Quotations
  "Now pray don't be troublesome, my dear gel," said Uncle Andrew.
  1955, C[live] S[taples] Lewis, The Magician’s Nephew, London: The Bodley Head