希臘文中常用的多义词，原義是「話語」（英語 word），但包含許多層面：

1. 讲话、话语、語言、对话、交談
2. 故事、叙述、说明、演說、论题
3. 消息、报告
4. 与事实相比较的话、言语
5. 命令
6. 思考、斟酌、权衡
7. 意见、观点
8. 原则、道理、原理、道
9. 原因、理由、理性、因果
10. 作品的“中心内容”。
11. 在公元前四世纪，还指“思考（能力）”或“说理的能力”。

亚里士多德《政治学》，吴寿彭译，商务印书馆，1965 年版，第 8 页；《政治学》，颜一、秦典华译，中国人民大学出版社，2003 年版，第 4 页

人和动物不同，因为人有 logos。

（亚里士多德有时用 logos 指“定义"或阐明事物性质和特点的语言。）

Logos，The American Heritage Dictionary of the English Language, Third Edition © 1992

1. Philosophy. a. In pre-Socratic philosophy, the principle governing the cosmos, the source of this principle, or human reasoning about the cosmos. b. Among the Sophists, the topics of rational argument or the arguments themselves. c. In Stoicism, the active, material, rational principle of the cosmos; nous. Identified with God, it is the source of all activity and generation and is the power of reason residing in the human soul.
2. Judaism. a. In biblical Judaism, the word of God, which itself has creative power and is God's medium of communication with the human race. b. In Hellenistic Judaism, a hypostasis associated with divine wisdom.
3. Theology. In Saint John's Gospel, especially in the prologue (1:1-14), the creative word of God, which is itself God and incarnate in Jesus. In this sense, also called Word.