What does the cryptic crossword clue "City in the Americas is, oddly, not a city in the Americas (7)" mean?

The wordplay uses an anagram. ONTA (synonym="ONTA") + RIO (synonym="‘city in the Americas’") = ONTARIO The answer is ONTARIO.

City in the Americas is, oddly, not a city in the Americas (7)

Guardian Cryptic #29594 | 26 Across | 2025-01-17 flower