ˌTrooping the ˈColour, the
a traditional British ceremony held every year in London on the official birthday of the Queen or King. Many soldiers on horses or on foot march across Horse Guards Parade carrying their ‘colours’ (=flags), and they salute the Queen or King as they march past. It is a very colourful ceremony and is popular especially with tourists.

[TahlilGaran] Dictionary of Contemporary English ▲