While yellow is generally the color of cavalry, here it stands for armor—the modern equivalent of the horse-mounted units. In the middle of the shield is what is known as a caltrop, a triangular figure also found in the unit's CSIB and whose highly appropriate meaning can only be found in older dictionaries. According to Webster's 1828 American Dictionary of the English Language, when a caltrop is used in association with the military, it is "an instrument with four iron points, disposed in a triangular form, so that three of them being on the ground, the other points upward. These are scattered on the ground where an enemy's cavalry are to pass, to impede their progress by endangering the horses’ feet." In other words, the caltrop displayed in III Corps Unit Crest is being viewed from an overhead perspective, with the white tip forming the point that would, in days gone by, endanger the horses' feet. The blue and white of the caltrop are the colors associated with a Corps for identification purposes. Unlike many Distincitive Unit Insignia's, the Unit Crest of III Corps does not feature the unit's nickname ("Phantom Corps").