ॐ नमः शिवाय defines my life

Sanatan Dharm is too vast and deep to be defined in one line. It's a popular misconception that Religion equals Dharma. It's not true because Religion is only a minuscule part of Dharma. It's a misnomer that they are exactly same and it's inappropriate to loosely use them interchangeably. Few attempts to define Dharma:
तादृशोऽयमनुप्रश्नो यत्र धर्मः सुदुर्वचः
दुष्करः प्रतिसंख्यातुं तर्केणात्र व्यवस्यति ९
प्रभावार्थाय भूतानां धर्मप्रवचनं कृतम्
यत्स्यादहिंसासंयुक्तं स धर्म इति निश्चयः १०
- भीष्म उवाच दशाधिक शततमोऽध्यायः शान्तिपर्व महाभारत
"Dharma" is that which upholds, nourishes or supports the stability of society, maintains social order and secures the general well-being and progress of mankind.
- Supreme Court of India
As India has recognised national flag, national bird, national anthem and national flower, the Bhagwad Gita may also be considered as the Rashtriya Dharma Shastra. The Gita inspired our national struggle for freedom and all walks of life,. It is the duty of every citizen of India under Article 51A of the Constitution of India irrespective of caste, creed or religion to follow the dharma propounded by the Bhagwad Gita,.
- Allahabad High Court