理学 元模型体系结构 释 object constraint language; OCL 对象约束语言 一种形式化的模型描述语言。用于描述统一建模语言（UML）模型的细节，既是UML规范的组成部分，也可视为一种独立的语言。
软件工程 释文 object constraint language, OCL 对象约束语言
- users and interactive information retrieval
- users authentication authorization
- user's collaborative information retrieving behavior
- users'cost of fisheries resources
- user's diary description
- user's exploratory searching behavior
- user's perspective study
- user's psychology-behavior control mechanism
- user stack
- user study
- user survey method
- uses and gratifications approach
- U set
- U-set
- Use the Language of the Motherland Correctly, Fight for the Purity and Health of the Language!（Editorial）
- use value
- use value of forest resource
- use value of resources
- U.S.FDA
- USFDA
- U.S. Federal Aviation Administration
- U.S. Food and Drug Administration
- U.S. Government Publishing Office
- U.S.Government Publishing Office
- U-shaped