Accent colour
A contrasting colour used in small amounts to draw attention or add life to a scheme.
Also: highlight colour, pop of colour
An accent is the colour used least and noticed most. In a room of greys it might be one yellow chair; on a web page, the colour of the main button. It works because it is rare, so it should be saved for the things that matter. A common rule of thumb for interiors divides a scheme into about sixty per cent main colour, thirty per cent secondary and ten per cent accent. In traditional Indian saris, a contrasting border and end piece do the same job against the body colour.