When you are producing a map at a scale where the labels are large with respect to the features or there are numerous features in a small area, you may be faced with a choice of not labeling features where conflicts occur or modifying the labels so that more will fit. The Maplex Label Engine allows you to choose from a number of space-saving styles.
Labels can be stacked, extended beyond features, reduced in size, abbreviated or truncated, or labeled with a key. You can apply one or more of these space-saving methods to produce the best result for your map.