UNKNOWN

x, y or z, possibly (7)

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

• Quick crossword No 16,538 — 2023-05-08 23:00:03
  5D: x, y, or z? (7)
• Quick crossword No 15,292 — 2019-05-12 23:00:44
  18A: x, y or z, possibly (7)