ARGON

Noble gas, Ar (5)

Solution has appeared in 4 crosswords (1 across and 3 down):

• Quick crossword No 15,953 — 2021-06-23 23:00:40
  5D: Gas — organ (anag) (5)
• Quick crossword No 15,696 — 2020-08-26 23:00:36
  20D: Gas, Ar (5)
• Quick crossword No 15,516 — 2020-01-30 00:00:01
  20D: Inert gas (5)
• Quick crossword No 15,388 — 2019-09-01 23:00:34
  19A: Noble gas, Ar (5)