“occasion / time” in Japanese is 際, read sai, kiwa (さい, きわ). It is a Grade 5 Kyōiku kanji, taught in year 5 of Japanese elementary school, and appears in words such as 国際 (international).
What does 際 mean?
別れの際に手をふる。
Same sound, different character — the classic trap. Compare them side by side: