| UDF (User Defined Functions) |
| UI - Fabric |
| UI (User Interface) |
| ui.closeContainer |
| ui.Dialog |
| ui.displayDialogAsync |
| ui.messageParent |
| Uncalled Function Checks |
| Undefined |
| Underscore |
| Underscore.js |
| Unidirectional Data Flow |
| Union Data Types |
| Unit Testing |
| unshift - Array Method |
| Urls - Resources |
| use strict |
| useDirectDebugging - Registry |
| User Defined Functions - Custom Functions |
| User Defined Functions (UDF) |
| User Interface (UI) |
| UserVoice |
| useShortNamespace |
| Using Existing Request Context |
| Using Previously Requested Object |
| UX Design |
| UX Design Patterns |
| UX Guidelines |
| UX Integration |
| UX Shapes |