vedyog.net

In English:

Swami Dayanand Saraswati Commentary : The one who maintains and protects from the time of conception to providing food, etc., hence the father is called ‘Guru = Teacher’; and the one who removes away the darkness of ignorance from the heart with his truthful advice, is also called ‘Guru i.e Acharya = Teacher’.

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In Hindi:

महर्षि दयानन्द व्याख्या : जो वीर्य दान से ले के भोजनादि कराके पालन करता है, इससे पिता को 'गुरु' कहते हैं, और जो अपने सत्योपदेश से हृदय का अज्ञान रूप अन्धकार मिटा देवे, उसको भी 'गुरु' अर्थात् आचार्य कहते हैं ।