UREA

Organic compound excreted in urine (4)

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

• Quick crossword No 16,684 — 2023-10-25 23:00:17
  22D: Human waste product used as a fertiliser (4)
• Quick crossword No 16,248 — 2022-06-03 23:00:20
  21A: Organic compound excreted in urine (4)