Old comment, but yes it technically does mean "3 Colours", but more specifically/often refers to a flag with 3 whole rectangles colours (Esp. vertical)
IE, The French, Italian, Belgian, Luxembourgish, Romanian, but also German, Dutch, Russian, Hungarian,
IE, The French, Italian, Belgian, Luxembourgish, Romanian, but also German, Dutch, Russian, Hungarian,
I only got the last one wrong.