What does the cryptic crossword clue "Operetta composed in a hotel (8)" mean?

The definition is "Operetta". The wordplay uses an anagram. anagram of IN + A + HOTEL = IOLANTHE; definition: "Operetta" The answer is IOLANTHE.

Operetta composed in a hotel (8)

Daily Mail Cryptic #17053 | 16 Down | 2023-03-14 flower