In English:
Sutra in English : Characteristic
Swami Dayanand Saraswati Commentary : by which the target is known, which is its natural quality, just as fire is known by the visible form, hence it is called ‘Characteristic’.
In Hindi:
महर्षि दयानन्द व्याख्या : जिससे लक्ष्य जाना जाय, जो कि उसका स्वाभाविक गुण है, जैसे कि रूप से अग्नि को जाना जाता है, इसलिये इसको 'लक्षण' कहते हैं।