「法印」是什麼？
What is the meaning of Dhamma-lakkhaṇa?
印就是印璽。國王的印璽可以證明文件的真實（有通行無阻的作用）。藉以比喻佛教的主要教義，也以符合「法印」而證明其為真正佛法（掌握了它，便能對一切法通達無礙），所以稱為法印。「諸行無常，諸法無我，涅槃寂靜」，並稱三法印，或者加上「有漏皆苦」，亦稱四法印。
Lakkhaṇa means mark or seal. An imperial seal certifies the authenticity of documents, allowing for passage without hindrance. Here, it is used in analogy for the principal doctrines of Buddhism. If any doctrine is in line with the "Seals of Dhamma", it can be regarded as authentic teaching of the Buddha. (If it has been mastered, all Dhammas will be grasped without obstruction.) That is why they are called the "Seals of Dhamma". If, after "All phenomena are impermanent, all dhammas are devoid of self", we add "Nibbāna is serene", we have what are called the Three Seals of the Dhamma. With the addition of " All defiled (sāsava) dhammas lead to suffering", we have the Four Seals of Dhamma.
來源：《佛教常識答問》趙樸初
Source: Answer to Common Questions
about Buddhism, by Zhao Puchu
翻譯：趙桐
Translated by: Zhao Tong
審譯：柯馬凱
English Editor: Michael Crook
校對：北京龍泉寺翻譯中心
Proofread by: Beijing Longquan Monastery Translation Center