What does the cryptic crossword clue "Key part of a crossword 25’s framework (8)" mean?

The wordplay uses a hidden word. GRID (synonym="‘key part of a crosswor’") + IRON (synonym="’25’ – golf CLUB") = GRIDIRON The answer is GRIDIRON.

Key part of a crossword 25’s framework (8)

Guardian Cryptic #29558 | 7 Down | 2024-12-05 flower