What does the cryptic crossword clue "Cipher once used in Belize routinely (4)" mean?

The definition is "Cipher". The wordplay uses a hidden word. Hidden in "cipher once used in beliZE ROutinely" The answer is ZERO.

Cipher once used in Belize routinely (4)

Times Cryptic #28652 | 26 Across | 2023-07-11 flower