旬 - decameron, ten-day period, season (for specific products)

last third of a month; 21st to the last day of a month

season (for fruit, seafood, etc.); best time of the year (for)

ten-day period (in a month)

first 10 days of the month

first third of a month; first ten days of a month

middle ten days of a month; 11th to 20th day of a month

Shavuot; Feast of Weeks; (Jewish) Pentecost

Pentecost

fish in season

ten days

ten-day period

Lent