What does the word "Halcyon" mean?

• The required answer is - Calm and peaceful.

• Halcyon (adjective)
English Meaning: A very happy or successful period in the past.
Bangla Meaning: শান্ত; দুর্যোগহীন: halcyon days/weather.

Example Sentence:
1. So I can totally understand why someone would want to recapture this halcyon period.
2. The halcyon, a mythical bird, is said to have laid its eggs in the nautilus' shell.

Source:
1. Cambridge Dictionary.
2. Accessible Dictionary by Bangla Academy.