LATEX

Plant material, used to make rubber (5)

Solution has appeared in 2 crosswords (1 across and 1 down):

• Quick crossword No 16,100 — 2021-12-13 00:00:52
  14D: Milky fluid found in poppies and other plants (5)
• Quick crossword No 15,656 — 2020-07-10 23:00:29
  21A: Plant material, used to make rubber (5)