The Cord systems signify the amount of time, knowledge and experience each player has and is worn around the waist, tied at the side of the hip (rather than in front like you might see in Karate).
Most modern Capoeira groups systems use coloured ropes, called corda or cordão. Many Groups have different systems, use different types of rope, and differ in the order of colours.
This is a look at the Kadara Capoeira International grading system.