What does the cryptic crossword clue "Lunar cycle related to a bone (5)" mean?

The definition is "related to a bone". The wordplay uses an anagram. anagram of LUNAR = ULNAR; definition: "related to a bone" The answer is ULNAR.

Lunar cycle related to a bone (5)

Guardian Cryptic #28946 | 17 Across | 2022-12-21 flower