We use a number of icons to try to reduce the amount of text on our website and keep it as simple as possible. Most of the times this icons are self-explanatory (at least we hope so), but here is a breakdown of all of them with their explanation.
ATP - Men's Tennis (atpworldtour.com)
WTA - Women's Tennis (wtatennis.com)
Warning Sign - Indicates that there is some very important news on this match. For example, in tennis it could indicate that a player has retired from one of his previous matches