This document introduces some vocabulary that is essential to understanding the Standard Label Engine and the Maplex Label Engine Help. Some definitions are linked to documents with more thorough descriptions.
Label
Descriptive text based on one or more feature attributes. Labels are placed dynamically on or near features based on user-defined rules and in response to changes in the map display. Labels cannot be individually selected and modified by the user.
Label class
A category of labels that represents features with the same labeling properties. For example, in a roads layer, label classes could be created to define information and style for each type of road: interstate, state highway, county road, and so on.
Label Manager
The Label Manager lets you view and change labeling properties for all the label classes in your map. It is used by both the Standard Label Engine and the Maplex Label Engine.
Text symbol
A text style defined by font, size, character spacing, color, and so on, used to label maps and geographic features.
Reference scale
A reference scale on your data frame forces your labels to scale as you zoom in and out. By default, labels do not scale; that is, they stay the same size on the page regardless of the map scale. Though they stay the same size on the page, they take up more geographic space on the map as you zoom out and less space as you zoom in.
Label priority
Label priority affects the order in which labels will be placed on the map. Labels with a higher priority are generally placed before labels with a lower priority. Also, lower-priority labels that conflict with higher-priority labels might be placed at alternate positions or dropped from the map.
Feature weight and label weight
A ranking system that indicates whether features and/or labels from a given feature class can be covered by a label in cases where the label cannot be placed in free space. Feature classes with lower weights tend to have labels placed over their features and/or labels before feature classes with higher weights. Polygon feature classes have two types of weights: boundary weights and interior weights. The Standard Label Engine uses feature and label weights. The Maplex Label Engine only uses feature weights.
Maplex Label Engine parameters
Maplex Label Engine parameters are user-specified properties that allow you to control the positioning, size, and format of your labels and also how conflicts between labels are to be resolved when the available space is limited.