MONO

Not stereo (4)

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

• Quick crossword No 16,627 — 2023-08-20 23:00:01
  18D: Acute disease characterised by fever and swollen lymph nodes (abbr) (4)
• Quick crossword No 15,574 — 2020-04-06 23:00:09
  19A: Not stereo (4)