Tricolour
A tricolour (three colours) is a flag or banner more or less equally divided (horizontally, vertically, or, less frequently, diagonally) into three bands of differing colours. The term is somewhat misleading, as many tricolours have more than three colours, as they are often charged with contrasting emblems (the flag of India as a prominent example).
Besides carrying an emblem, another means by which a tricolour may have more than three colours is through the use of fimbriation: the separation of colours on a flag by a narrow contrasting stripe. In a fimbriated tricolour, the three broad bands are separated by two thin stripes on either side of the central band. Flags of this type include the flags of the Gambia, Kenya, Namibia, Tanzania, and Uzbekistan.
Variety of triband
The tricolour is a specific type of triband. In a triband, the design is of three vertical, horizontal, or diagonal stripes, often formed—from a heraldic point of view—by the placement of a vertical or horizontal stripe (a pale or a fess, respectively), over a background. The triband may thus have two stripes of the same colour split by a stripe of a second colour (examples of this include the flags of Argentina, Austria, Barbados, Belize, Cambodia, Canada, Colorado, El Salvador, French Polynesia, Georgia (U.S. state), Guatemala, Honduras, Laos, Latvia, Lebanon, Mongolia, Nicaragua, Nigeria, Norfolk Island, Peru, and Spain).
In a tricolour, the two outer stripes are of different colours. They can thus be seen as a subset of tribands.
Additional meanings
Vexillologists also occasionally describe flags of which the main element is three stripes as being "based on a tricolour (or triband) design". Flags such as the flag of the Bahamas and the Palestinian flag fall into this category.
Some vexillologists take the meaning of the term at its barest, and simply use it to describe any flag containing just three colours, irrespective of the design. Thus, the flags of the United States and the United Kingdom might be described as tricolours, while the flag of India (which has a blue charge in the centre) would not.
Examples
Horizontal
Horizontal charged
Vertical
Vertical charged
Diagonal
Diagonal charged
See also