THORIUM

Radioactive element — rout him (anag) (7)

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

• Quick crossword No 16,047 — 2021-10-11 23:00:02
  21A: Radioactive element used in nuclear reactors — trio hum (anag) (7)
• Quick crossword No 15,352 — 2019-07-21 23:00:07
  15D: Radioactive element — rout him (anag) (7)