flag day
Concise Oxford English Dictionary © 2008 Oxford University Press:
flag day
▶noun
- 1 Brit. a day on which money is collected in the street for a charity and contributors are given small paper badges to wear.
- 2 (Flag Day) (in the US) 14 June, the anniversary of the adoption of the Stars and Stripes in 1777.
'flag day' also found in these Oxford entries:

