tricolour
Concise Oxford English Dictionary © 2008 Oxford University Press:
tricolour /ˈtrɪkələ, ˈtrʌɪkʌlə/ (US tricolor)
▶noun a flag with three bands or blocks of different colours, especially the French national flag with equal vertical bands of blue, white, and red. ▶adjective (also tricoloured) having three colours.
'tricolour' also found in these Oxford entries:

