The phrase "many happy returns" is a traditional birthday greeting that expresses good wishes for the person celebrating their birthday. The full expression is often "Happy Birthday! Many happy returns of the day!"
The origin of this phrase can be traced back to at least the 18th century. The word "returns" in this context refers to the recurring annual event of the person's birthday. When we say "many happy returns," we are essentially wishing the person many more happy birthdays to come in the future.
The use of the word "returns" is akin to saying that the joy and happiness experienced on the current birthday should come back again and again with each passing year. It's a way of expressing the hope that the person's life will continue to be filled with happiness, blessings, and good fortune in the years ahead.
While the phrase has become a common birthday greeting, it's worth noting that the exact origins and earliest usage of the expression may be challenging to pinpoint, as language and customs often evolve over time. Nevertheless, it remains a warm and heartfelt way to extend good wishes to someone on their special day.